Despite limping in behind George Misch's Calling Hedy Lamarr (2004), Donatello and Fosco Dubini and Barbara Obermaier's Hedy Lamarr: Secrets of a Hollywood Star (2006) and Johanna Gibbon's 2011 contribution to the BBC's Extraordinary Women series, Alexandra Dean's Bombshell: The Hedy Lamarr Story cracks on as if it has scooped the world to revelations about the Austrian actress's screen career, troubled private life and remarkable achievements as an inventor. Admittedly, the debuting Dean has done well to secure interviews with all three of Lamarr's children and makes a decent job of marshalling the wide-ranging audio and visual material. But it's far too simplistic to claim that Lamarr was solely a victim of her beauty and the institutional chauvinism of the Hollywood studio system when her travails were clearly caused by a combination of these factors and both her own vanity and a psychological fragility that prompted her repeatedly to make poor decisions in her private and professional relationships.

`Any girl can look glamorous,' Hedy Lamarr once said. `All she has to do is stand still and look stupid.' Billed as `the most beautiful girl in the world', Lamarr was the model for Disney's Snow White and DC Comics's Catwoman. Yes, as Google animator Jennifer Hom insists, she was akin to a secret crime fighter, as she spent her spare time working on inventions that changed the world. Friend Mel Brooks and son Anthony Loder suggest she was judged on her looks when she should have been valued for her mind.

On Merv Griffin's chat show in the 1960s, Lamarr claimed she was `a simple complicated person' and Dean discovers no better way of defining her subject over the ensuing 85 minutes. Granddaughter Wendy Colton regrets that Lamarr never got round to writing the autobiography that would have set the record straight, but Dean is happy to use the four-cassette interview that Forbes journalist Fleming Meeks conducted with the 76 year-old Lamarr in 1990 to provide the framework for her story.

Born Hedwig Eva Maria Kiesler in Vienna in 1914, the young Hedy was inspired by her banker father Emil to explore how the world worked. At five, she took her musical box apart and re-assembled it and biographer Richard Rhodes and archivist Jan-Christopher Horak sketch in details of her happy childhood with her wealthy, cultured parents. But, film historian Jeanine Bainger insists that her ambitions to become a scientist were derailed by her beauty. However, Hedy was well aware of how to exploit her looks and admits to Meeks that she was an `enfant terrible', who posed nude for photographs at 16 before taking her first minor screen roles at Sacha Studios in 1930.

Her destiny was sealed, however, when she appeared naked and simulated an orgasm in Czech director Gustav Machatý's Ecstasy (1933), which upset Pope Pius XI on grounds of taste and Adolf Hitler because Hedy was Jewish. Director Peter Bogdanovich and scandal specialist Anne Helen Petersen tut in unison about the sensational nature of the picture. But Lamarr tells Meeks that she merely did what she was told by Machatý, who threatened to stab her with a needle through the sofa to get the expressions he wanted. She recalls her father's disappointment with her comporting herself in such a manner and, as a result, she took the lead in Fritz Kreisler's opera, Elisabeth of Austria, and regained Emil's respect when she received rave reviews.

A few months later, the 19 year-old Hedy married munitions tycoon, Fritz Mandl, who was 14 years her senior. He treated her as a trophy wife who could entertain such illustrious house guests as Benito Mussolini. Actress Diane Kruger (who reads from Lamarr's writings throughout the film) denounces important men who treat women as eye candy, but hints that Hedy was also intrigued by the power she could wield through her beauty.  She also informs Meeks that she enjoyed the luxurious lifestyle, even though one of the voices off insists that she was bored witless by the titans of industry she met at swish social affairs. Lamarr also declares that Mandl refused to let her near the factory, which supplied arms to Hitler, even though he refused to consort with Mandl because he was Jewish.

Biographer Stephen Michael Shearer suggests that Hedy grew tired of Mandl's possessiveness, although the threat of an imminent Nazi incursion into Austria also influenced her decision to disguise herself as a maid and flee by bicycle, with her jewellery sewn into her uniform. This episode is recreated in a stylised cartoon form that rather confirms the speculative nature of the narrative, as nobody seems entirely sure what Lamarr's motives were in fleeing to London in 1937. It was here that she decided to pursue her screen career after she ran into MGM chief Louis B. Mayer on a talent-scouting mission. Unhappy with his meagre contract offer, she followed him aboard the SS Normandie and made sure that he saw the reaction of every man on the liner in her bid to secure a more lucrative deal.

Renamed by Mayer's wife Margaret Shenberg after her favourite silent star, Barbara La Marr (who was known as `The Girl Who Was Too Beautiful'), Hedy cooled her heels while she studied English and only landed her first role, in John Cromwell's Algiers (1938), when Charles Boyer became entranced at a party and insisted on her being cast alongside him. This exotic remake of Julien Duvivier's Pépé le Moko (1937) made her an overnight sensation. But Mayer had no idea what to do with her - she would have been much better off at Paramount - even though Joan Bennett, Myrna Loy and Vivien Leigh all copied her centrally parted hairstyle. Mel Brooks says he wanted to go to Hollywood to marry her (or simply feel her up under the table - charming!).

Friend Robert Osborne reveals that the woman behind the sophisticated image enjoyed having fun. But she could also spring surprises, such as her second marriage to portly screenwriter Gene Markey. In a letter to her mother, Gertrude, she notes that he reminded her of Emil and the 23 year-old seemed genuinely smitten. Yet, shortly after they adopted a son, James, Markey cheated on Lamarr and she was shattered by the ensuing divorce. However, her anger goaded her into demanding better roles from MGM and the acclaim for her performance in Jack Conway's Boom Town led to further success in Clarence Brown's Come Live With Me, King Vidor's Comrade X and Robert Z. Leonard's Ziegfeld Girl (all 1940).

At no point, however, does Dean pause to assess Lamarr's qualities as an actress. Instead, Anthony Loder and sister Denise Loder-DeLuca protest that their mother was treated like a racehorse and forced to follow a regimen of sleeping and pep pills to ensure that she always looked her best in front of the camera. Yet, as friend Roy Windham intimates, Lamarr was more interested in showing mogul-cum-aviator Howard Hughes how to improve their aerodynamism of his latest plane by studying birds and fish. Her bid to create cola cubes proved less successful, but Lamarr never stopped having ideas.

Although manicurist friend Manya Breuer recalls Lamarr's refusal to admit to her Jewish ancestry, she remained committed to the fight against Fascism. Thus, even though the United States was still neutral, she began collaborating with avant-garde composer George Antheil on solving the problem of U-boats jamming the radio signals being beamed to torpedoes in the North Atlantic. Historian Guy Livingston and Loder explain how she hit upon the idea of `frequency hopping' to prevent the submarines latching on to the radio transmissions.

The Pulitzer Prize-winning Rhodes recalls how engineer Robert Price claimed Lamarr stole the idea from one of Mandl's contacts and physicist Tony Rothman recalls Price comparing Lamarr to Mata Hari. But Rhodes insists that the Germans had not been working on such technology and posits that she might have been inspired by a remote control dialling device marketed by Philco. We see it being used in a clip from Norman Z. McLeod's Topper Takes a Trip (1941) and Loder finds references to the Magic Box in his mother's papers.

Professor Danijela Cabric and inventor Nino Amarena aver that genius isn't always rooted in academic intelligence and credit Lamarr with recognising that Antheil was her ideal collaborator. She had written her phone number in lipstick on the windshield of his car after meeting him at a party and conductor Michael Tilson Thomas reveals how she had recognised how the synchronisation apparatus he had perfected for Ballet Mécanique, his 1924 piece for 16 player pianos could be adapted to programme random torpedo codes.

Off-screen voices claim that Antheil teamed up with Lamarr because he wanted revenge for his younger brother's death. However, his plane was shot down by a Soviet fighter and it's not clear how building a device to confound Nazi subs would get Antheil even with Joseph Stalin. Nevertheless, the pair submitted their proposals to the US Navy in Washington, only to have their patent shelved for being too fanciful to be practical. But, as Antheil's nephew, Arthur McTighe, points out, their idea to create a secret communication system using frequence hopping now underpins such staples of modern living as cellphones, wifi, satellites and GPS.

As Antheil had bills to pay, he decided not to refine the design and the 27 year-old Lamarr was hugely disappointed (speculates one off-screen voice) not to be given the opportunity to prove that she was more than just a pretty face. But, even though she was not yet a US citizen, she felt sufficiently patriotic to sell $53 million-worth of war bonds and was frequently on duty signing autographs and selling kisses at the Hollywood Canteen. Yet, in 1942, the government saw fit to confiscate her patent as the property of an enemy alien.

During this period, Lamarr kept making pictures like King Vidor's HM Pulham, Esq (1941) and Robert Siodmak's White Cargo (1942), in which she infamously played a seductive African native named Tondelayo. However, Dean opts against discussing the film's representation of race and follows the off-screen voice that asserts that Mayer divided women into madonnas and whores before proclaiming that Lamarr always believed she was the latter because of Ecstasy. It's true that MGM put a woman who had invented a gadget that could have made a major impact on the war into a sensationalist potboiler designed to give frontline troops a glimpse of female flesh. But such a sweeping statements does little for the documentary's overall credibility, especially as we don't get to see who made it.

Having described how Lamarr came to resent Mayer for devaluing her and suffered suspension as a consequence, Dean leaps forward four years to the two features that Lamarr produced for herself: Edgar G. Ulmer's The Strange Woman (1947) and Robert Stevenson's Dishonored Lady (1947). Instead of exploring the boldness of such a step at a time when few actors were producing their own films within the studio system or analysing the quality of the work, Dean notes that Lamarr married her British co-star of the latter project, John Loder. Denise and Anthony clearly have little time for the father who abandoned them and they understandably lavish praise on their mother for making them feel loved at a time when she was being rejected by her profession as well as her husband.

A stroke of luck returned Lamarr to the cover of the Tinseltown fanzines, as Cecil B. DeMille paired her with Victor Mature in his glitzy Technicolor biblical epic, Samson and Delilah (1949). Once again, however, Dean offers no evaluation of the picture or Lamarr's performance and fails to consider in any detail why her bid to produce a costume epic of her own in Europe turned into an artistic and financial millstone. Directed by Marc Allégret and Edgar G. Ulmer, Loves of Three Queens (1954) failed to find an American distributor and left Lamarr in the dire straits that prompted her to marry oil tycoon W. Howard Lee. But Dean is in too much of a hurry to discuss the end of Lamarr's movie career and whisks us off to Texas, where Anthony and Denise had a nice time while their mother designed a ski chalet in Aspen, Colorado. However, Lee was an alcoholic and Lamarr decided to leave him to spare the children. Unfortunately, on the day she was supposed to testify in court, her 11 year-old son was seriously injured in a traffic accident and the judge decided to punish her for sending her studio stand-in to give evidence in her place. As a consequence, she lost the ski resort and suffered a nervous breakdown.

In speaking to Meeks, Lamarr claimed to have been dead for a while, as she saw her father in a bright light on the ceiling and granddaughter Lodi Loder claims that he was always the love of her life. However, Lamarr was capable of great coldness and Denise remembers the surprise of discovering she had an adopted brother and learning that James had been placed in a military boarding school after proving disruptive. When he asked if he could live with the coach and his wife, Lamarr disowned him and he reveals that they didn't speak again for four decades. Nevertheless, he continued to love her and refuses to blame her for the breaking of the bond. Anthony suggests that his mother had pieces missing to be able to jettison her Judaism and her son in such a manner. But he also insists that her increasingly erratic behaviour could be put down to the drugs to which she had become addicted during her time at MGM.

However, Lamarr also became involved with Max Jacobson and `Dr Feelgood' biographer William J. Birnes reveals that his famous vitamin elixirs were actually methamphetamine injections. Anthony claims these shots turned his mother into a monster, but Denise says she was a victim of the studio that used her up and wore her out. Yet, Lamarr continued to exploit her fame in order to survive in the 1960s. Although she had stopped acting, she remained a popular guest on chat and panel shows. However, she was hurt when Lucille Ball parodied her performance as Tondelayo in a 1965 episode of I Love Lucy, although she was more humiliated by a shoplifting charge the following year, which coincided with the publication of Ecstasy and Me, which had been ghostwritten without her full approval by Leo Guild and Cy Rice.

Although she was acquitted, Andy Warhol mocked her fall from grace in Hedy, or The 14 Year Old Girl (1966), in which she was cruelly played by drag queen Mario Montez. As a result of the scandal, Lamarr was denied her screen comeback in Bert I. Gordon's Picture Mommy Dead (1966) when her role was awarded to Zsa Zsa Gabor. In her 1969 interview with Merv Griffin and a young Woody Allen, Lamarr denied having an image to live up to. But she had started having plastic surgery in her forties and Dr Lisa Cassileth claims that many contemporaries asked for procedures similar to the ones that she had helped devise. However, the more surgery she had, the more damage she did to her face and she became something of a recluse.

In a German tele-interview (which provides the basis for the Dubini-Obermaier documentary), she expresses her homesickness and wishes she could make a film about the Viennese sights and sounds that had so enchanted her as a girl. As Lodi Loder reflects on the fact that she only met her grandmother twice in person and that the photos she sent her were studio glamour shots, we learn that Lamarr was left to exist on a stipend from the Screen Actors Guild and social security. Yet, the frequency hopping idea had been appropriated by the US Navy in time for the Cuban Missile Crisis after they had allowed the patent licence to lapse so they could use it without paying royalties. However, frequency hopping expert David Hughes reveals that government scientist Romuald Irenus had harnessed the technology for a sonobuoy in 1955, a full four years before the patent expired. Moreover, he later thanked Lamarr on his website for the idea that had helped him make his breakthrough in creating sonobuoys and surveillance drones.

Meeks broke the story of Lamarr's scientific achievements in 1990 and she lived long enough to get recognition for her pioneering theories. Major Darrel Grob explains how the US Air Force's Milsatcom network relies on Lamarr and Antheil's designs. In 1997, Anthony went to collect a belated Milstar Award and his mother phoned him in the middle of his acceptance speech. He played a tape-recorded message in which she thanked them for their kindness in honouring her. But she never received a dime before her death in January 2000 at the age of 85.

As a closing caption gauges that her invention would now be worth $30 billion, Dean leaves us with a lot of unanswered questions. If Lamarr was such a gifted inventor, why didn't she turn her hand to other projects in later life? Similarly, if she was so fiercely independent, why did she marry six unworthy husbands and come out of each marriage with little to show for it? What relationships did she retain within Hollywood and did she make any effort to relaunch her showbiz career after Harry Keller's The Female Animal (1958)? Why did she never get round to her autobiography after she had been so badly misrepresented by Guild and Rice? And why did she send a body double to court when she had a perfectly valid reason for postponing her appearance?

In fact, even when she does delve more deeply, Dean only provides sketchy explanations for Lamarr's inability to sustain relationships, her psychological decline and her ruinous dalliances with drugs and plastic surgery. A home-movie clip of her ravaged face is saddeningly shocking and one is left to wonder where the supposedly impoverished actress got the money for such procedures and why no one tried to dissuade her from having them. It's frustrating that Dean pays so little heed to Lamarr's filmography, as she is nowhere near as negligible an actress as most critics would have you believe. Much more attention should have been paid to her bid to branch out as a producer and to make a proto-feminist stance against the misogyny of the studio machine.

Yet, despite these demerits, this is a sincere attempt to give Lamarr her long-denied due (surely it wouldn't kill one of the communications giants to name a product after her?). Far too many of talking heads have little to contribute, while several of the more salient points are made without on-screen attribution. Moreover, Dean might want to revisit the segments on Louis B. Mayer and his treatment of his female stars in light of the Harvey Weinstein scandal. But this still makes an informative introduction to a woman who should be a household name because of her intellect rather than her iconicism.

China's most celebrated dissident artist is no stranger to film, as he makes his own, as well as appearing in such documentaries as Matthew Springford's Ai Weiwei: Without Fear or Favour (2010), Alison Klayman's Ai Weiwei: Never Sorry (2012) and Andreas Johnsen's Ai Weiwei: The Fake Case (2013). Instantly recognisable, Ai Weiwei runs the risk of being a bit of a distraction in Human Flow, as he keeps popping up in unlikely places while seeking to expose conditions in some of the world's biggest refugee camps. Nevertheless, the footage captured by 25 different camera crews should alert audiences to the efforts being made by governments and charitable organisations alike to combat poverty, persecution and extremism and to the ignorance, prejudice and fear that has driven 65 million people from their homes in recent times.

Following a towering aerial shot picking out a small craft speeding across the Mediterranean, we cut in to see a large rubber dinghy being escorted to shore. It is crammed with people, who are wrapped in foil blankets and offered tea, as Ai Weiwei takes photographs and offers his concern to a young man who has come from Salah Al-Din in Iraq. A drone shot looks down on a tented camp, as a caption reveals that there are 277,000 refugees in Iraq, the majority of whom are trying to flee the country. A second note explains that 268,000 have been killed since the 2003 US invasion, while more than four million Iraqis have been forcibly removed from their homes. Two women recall the bombardment that drove them away, as a drone hovers over a decimated settlement and Ai poses various ordinary people in front of a blank screen to reinforce the idea that the occupants of the camp are human beings like the rest of us.

The 1951 United Nations definition declares a refugee to be a person with `a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion'. Nocturnal footage shows a boat coming ashore at Lesvos, as a newspaper headline claims that 56,000 souls are arriving in Greece each week during peak sailing periods. A caption confirms that over a million refugees arrives in the country during 2015-16, with the majority coming from Afghanistan, Iraq and Syria. Ai surveys the coastline and learns from UNHCR Communications Officer Boris Cheshirkov that this is the largest mass movement of people since the Second World War.

Scenes show the Lesvos arrivals boarding a ship to be resettled in Sweden, Germany and other European countries. Many of the passengers take photos on their phones and a young father tells the camera that he hopes to find a home in a place where he is accepted. A small child fusses over a pair of boots and there is a sense of  optimism that the worst is over, as a caption repeats Angela Merkel's hope that Europe can cope with the crisis.

The scene shifts to Bangladesh, as a small rope ferry crosses a placid patch of water. But, as Rohingya community leader Ustaz Rafik reveals, things have been anything but peaceful for this Muslim minority in Myanmar, as settlements have been destroyed, women have been raped and innocent victims have been killed without resistance. As a result of what many believe to be a concerted policy of ethnic cleansing, 500,000 Rohingyas have fled to Bangladesh, Thailand and Malaysia. Rafik laments the need for his people to leave their ancestral lands and is dismayed by the lack of respect for their basic humanity.

Back in Northern Greece, we see a column of refugees trudging through the countryside on a dank day. They cross a rushing stream and skirt muddy fields to reach the Macedonian border, where they are greeted with a barbed wire fence. Some 13,000 refugees occupy a makeshift camp near the village of Idomeni and the camera roams a settlement that is traversed by a busy railway line. Ai tries to cheer up a small boy by doing a drawing for him and he smiles. But, according to Peter Bouckaert from Human Rights Watch, there is nowhere for them to go and conditions are already deteriorating.

Another caption reveals that the number of countries with border fences and walls has increased from 11 to 70 in the period since the Berlin Wall was toppled in 1989. On the Serbian-Hungarian frontier, there is a camaraderie among the border guards and Filippo Grandi, the UN High Commissioner for Refugees, compares the situation to the Cold War when smaller numbers sought sanctuary from the Soviet bloc. But Europe was not ready for such a mass influc and has been improvising policies since 2015, with the result that the individual responses trap thousands of helpless strangers with no option but to stay put and hope.

Over an aerial shot of a camp on the Syrian border with Jordan, a caption details that 1.3 million have fled the civil war and we see troops escorting people through an official entry point before they are driven away in trucks. Another caption explains that Jordan has become home to over two million Palestinians since 1948 and Ai cooks kebabs in a busy market place in one of the camps. Some have become so large that they have developed their own economies and we see one camp with its own artificial football pitch.

Jordanian princess Dana Firas tells Ai that the average refugee spends 25 years away from home and she hopes her nation keeps offering sanctuary, as it reminds citizens of the need to maintain their own status quo and to be a good neighbour. According to the Washington Post, 75,000 Syrians are trapped on the Jordanian border and, having filmed a camel at some ancient ruins, Ai sends a drone over another vast tented settlement in the middle of the desert.

From here, he goes to Southern Italy, where over 210,000 refugees arrived from Afghanistan between 2015-16. We see a group of men being herded off a boat by troops and dressed in white boiler suits to be frog-marched along the quay. Others are wrapped in foil capes by soldiers and civilians wearing face masks that give off a signal that the newcomers are as unwelcome as any potential diseases they may be carrying  No wonder Hanan Ashwari, the head of the Palestinian Liberation Organisation's Department of Culture and Information, says that refugees are open to forms of cruelty that are not always intended.

Hundreds spill off a boat in Athens and wander the city centre. Ai films them on the road and asks a woman with her mother and daughter what she plans to do because the Macdeonian border has been closed. She shrugs and gets cross with the daughter, who is wearing a balloon hat that keeps poking her mother in the face. The girl (who is also holding a couple of balloon animals) giggles charmingly, as, while she has no idea of the gravity of her situation, she finds the balloon prodding her mother to be highly amusing. Ai buys oranges from the back of a truck before we hear a young man with his back to the camera describe why he paid traffickers to get him out of Iran and the trials he has endured since crossing into Turkey and then Greece.

A drone shot surveys that pitiful scene at Idomeni, as the wind whips the tents and Ai picks his way through the puddles to take more pictures. A woman suggests that some of Europe's leaders should spend some time in the camps and see the reality for themselves. Another feeds her ginger-and-white cat, Taboush, and shows Ai a photo on her phone on her phone of the creature wrapped in a special costume. Ai swaps passports with a man named Mahmoud and says he respects him and his right to belong and declines the offer to take his tent.

Moving to Eastern Turkey, we meet a couple who are among the 30 million Kurds living in the region that straddles Turkey, Iraq, Iran and Syria. They explain how the used to have a nice life with their own vegetable garden. But the struggle for political and cultural autonomy has cost them their homes and their livelihood. As we see the rubble in one settlement, a caption says 500,000 Kurds were displaced during a Turkish crackdown in 2015. Cameras prowl inside shelled homes, as people try to salvage belongings and a couple of people lament the damage and the senseless loss of life. But Ai opts not to discuss the reasons for the scenes he surveys. He is solely interested in the collateral damage and its impact on those whose lives will never be the same again.

Over a slightly contrived image of a moth flying up against a wire fence, a caption reveals that Turkey and the European Union reached a deal in March 2016 to restrict the numbers being allowed on to the continent. In return for being allowed to send back unwanted migrants, the EU promised Ankara €6 billion and visa-free travel. Emboldened troops fire tear gas into the camps and we see frightened children clinging to their grandparents and young men clashing with riot police. Ai has his head shaved in solidarity with the refugees, as we hear a couple of brothers vowing to press on to Germany, as they cannot abandon their dream. A woman with her back to the camera complains that no one has helped her apply for asylum and Ai (with a full head of hair) sits with her and offers a bucket when she vomits. Despite sit-down protests, thousands are deported and the authorities try to stop the crews from filming, as they are loaded on to boats and sent back to the nightmare from whence they came.

A towering aerial shot reveals the layout of another enormous camp, with the residents scurrying around like ants. Turkey now holds the most refugees in the world, with the majority of the three million having fled from Syria. However, only 10% live in official camps, with the rest receiving little or no humanitarian aid. Dr Cem Terzi of the Association of Bridging Peoples tries to treat some of the sick, but bemoans the fact that his compatriots aren't really interested in helping them. He despairs that they have no rights and can be moved at the whim of politicians grandstanding to their electorates. A man named Sediqi shows the camera a row of graves and the ID cards of the five family members who drowned trying to reach Europe. He sobs in the rain, as he reveals that he dreams of those he failed to save. His pain is palpable.

Lebanon hosts two million refugees from Palestine and Syria and they make up a third of the country's entire population. As kids clamour to give the peace sign to the camera at the Ain al-Hilweh camp, Tanya Chapuisat from UNICEF explains that several generations have been raised here, but few Syrian kids receive more than a rudimentary education. Maya Yahya from the Carnegie Middle East Centre suggests that such a situation leaves them vulnerable to exploitation and radicalisation. Druze leader Walid Joumblatt tells Ai that Europe has a very hypocritical approach to refugees, as they pay to keep them away. But Lebanon has slipped down the order of importance and they are struggling to integrate more outsiders into an already delicately balanced society. He insists they will continue to look to the future, but implies that he thinks it's bleak.

Ai wheels a suitcase through a checkpoint before a caption outlines the plight of the Palestinians, who are the world's biggest refugee group, with 4.7 million being cooped into the West Bank and the Gaza Strip. We see armed brigades driving through the streets and being hailed as heroes, as Ai films through a gap in the Defence Wall, which is covered with paramilitary murals and tributes to martyrs. As Israel and Egypt have been blockading Gaza since 2007, 80% of the population depends on humanitarian assistance. Over shots of penned queues waiting to go through a checkpoint, Hagai El-Ad from the Israeli B'Tsalem group decries the injustice that this represents. Ai meets a group of young women, who claim Gaza is a large prison and, yet, they somehow remain cheerful enough to joke about their situation.

A laboured top shot on to a tiger circling in a confined space presages an explanation from Dr Amir Khalil from Four Paws that the big cat named Laziz was smuggled through the Gaza supply tunnel. He organises papers for it to be taken to South Africa. For the humans trapped in the enclave, however, there is no easy escape and we see the whole settlement fall into silence as power cuts disrupt life on a regular basis.

The earliest human migration took place 140,000 years ago and Ai returns to Kenya because 26% of the world's refugees reside in sub-Saharan Africa. A dust storm blows up as a result of global warming and Ai photographs people moving like spectres through the parched landscape. He also goes to Dadaab, which is the biggest refugee complex on the planet, with 500,000 sheltering here from civil war and famine in Somalia, Eritrea and South Sudan.  Ai films goats looking for somewhere to graze on the parched terrain, as we meet Wella Kouyou from UNHCR, who reveals that numbers are rising as resources are dwindling and 250 million Africans are expected to experience drought, hunger and disease because of climate change, as the continental population rises to 2.5 billion by 2050.

Captions inform us that Pakistan has accepted three million Afghans since the Soviet invasion. However, many are now being deported for security reasons and we see mud huts being demolished in a cleared settlement. Marin Din Kajdom and Maya Ameratunga from UNHCR state that many have answered a rallying cry to rebuild their shattered country and we see a convoy of brightly painted lorries heading through the mountains. Ahmed Shuja from Human Rights Watch explains that many have been away so long that they are not able to return to their tribal lands and face difficulties in establishing themselves in alien territory. But, as least they will be citizens of their own homeland again.

Leaving men building new mud dwellings, we land in Berlin, where Ai films people lined up at Templehof, as a caption reveals that 1.2 million arrived in Germany seeking asylum between 2015-16. Manager Pascal C. Thirion takes Ai over the layout of the airport, while a drone hovers over the booths that have been partitioned out inside. Maria Kipp from Tamaja Shelter says the key task is to make them feel human again, although one teenage girl complains that she is bored and is tired of being told what to do.

In Paris, African migrants sleep rough on the street and one man is saddened that the democracy he had heard so much about is so ineffectual. Further north, 10,000 live in The Jungle outside Calais in the hope of crossing to Britain. Over views of the camp, Greek migration minister Ioannis Mouzalas says the only way forward is in union to combat isolationism and xenophobia. But, as we see The Jungle being demolished, it seems as though national interests are consistently being put before those of the migrants seeking a better life.

Back in Iraq, Mosul falls to Islamic State and refugees flood out of the second city. A caption blames the rise of ISIS on the 2003 invasion by the Coalition of the Willing and notes that the recapture of Mosul led to ISIS destroying the oil fields and putting 300,000 out of their homes. Angry orange flames fill the black smoked-sky, as people wander through their devastated neighbourhoods. One man missing half of his right arm describes how the fundamentalists treated the women they found on the streets, as a cow wanders through the rubble as though in a surrealist dream sequence.  But this is all too real for those with their belongings on their backs, as they look for somewhere safe to stay.

Out on the Mediterranean Sea, a patrol boat scours the horizon for rafts. According to a caption, over 5000 drowned trying to cross to Europe in 2016, while another claims that 34,000 flee their homes every day because of famine, poverty or war. A blue boat filled with Africans in orange life jackets is picked up and health workers describe the emergencies they had to deal with, including eight pregnancies. Happy to be safe, some of the women sing and clap in the holding hall.

Despite John F. Kennedy's assertion that only one group of Americans has not immigrated, the border with Mexico is now partially walled and vigorously patrolled. A patrolman asks Ai what he is filming and helpfully points out where the US ends and Mexico begins. As Ai cuts a Mexican migrants hair outside their shack near the border, we hear human rights activist Gabriela Soraya Vázquez state that everyone is entitled to move to better themselves. Kemal Kirisci, Senior Fellow at the Brookings Insitution avers that social media has helped spark the current upsurge, while globalisation has also had a double-edged effect and much will depend for the future on how well people from different cultures and religions learn to live together in a shrinking world.

Syrian astronaut Mohammad Fares concurs, as he saw people sharing a single, fragile planet when he was in space - which he thinks is a good place for the evil people who spoil life for the rest of us. Final shots take us over camps across the globe and we are left with a sense of the magnitude of the problem and the difficulty that humankind faces in not just accepting the right of others to exist, but also to improve, prosper and worship without prejudice.

Numbering Christopher Doyle among its cinematographers and including quotations from the likes of Baba Tahir, Nazim Hikmet, Sherko Bikas, Mahmoud Darwish, Nizor Qabbani and Ali Ahmad Said Esber (aka Adonis), this is always as much an artwork as a piece of advocacy. It also comes perilously close to a vanity project, as Ai Weiwei inserts himself in situations as a hale fellow well met when his absence would not in any way diminish the potency of his message. That said, Ai knows all about displacement after being caught up in the Cultural Revolution and, if his presence helps the film reach the widest possible audience, his cameos are a minor irritation worth enduring. As are the occasionally illegible captions and subtitles (why do they always insist on fixing white text to light areas of the frame when they could so easily use another colour or thicken the letter edging?).

But nothing should detract from the fact that this is a compelling and provocative encapsulation of a problem that should shame us all. What is so remarkable about the people depicted here is the combination of dignity and determination that enables them to face each fresh challenge with fortitude and faith. Ai opts not to name any of the migrants he interviews, but he also avoids patronising them in allowing them to speak their minds. Moreover, he and editor Niels Pogh Andersen also tellingly juxtapose God's eye viewpoints with earthbound close-ups to put the issues in perspective. But he might have identified the camps, as their names are bywords for the insularity and intolerance that blights our world. 

Bruce Parry will be known to millions for TV series like Tribe (2005-07), Amazon (2008) and Arctic (2011). However, the onetime Royal Marine and Trekforce expedition leader has clearly had a lot of time to think while on his travels and he ventures on to the big screen to share some of the wisdom he has accrued in Tawai: A Voice From the Forest. Co-directed by Mark Ó Fearghail (aka Mark Ellam), this sincere study of ancient approaches to sustainable living takes its title from the sense of oneness with the forest practised by the Penan people of Sarawak. There's no doubting Parry's conviction or courage and his encounters with the remote tribes in Borneo and the Brazilian Amazon are genuinely poignant. But, while the ideas he posits to recalibrate Western civilisation have a certain potency, he doesn't always communicate them in the most cogent manner and many will feel a bit put off by the New Ageiness of the otherwise laudable message.

Over clips from some of his BBC adventures, Bruce Parry commends humanity for finding such diverse ways to live. But he worries that we are putting such a strain on our fragile planet that we need to find new ways of co-existing with each other and the natural world. Convinced that we have much to learn from traditional societies, Parry decides to revisit the Penan of Ba' Puak in the Borneo rainforest, who are one of the last hunter-gatherer peoples on Earth. However, even they are being forced to settle and cultivate land in order to stake a claim on the forest the Malaysian government is hoping to exploit to produce palm oil.

So light is the nomadic Penan footprint that they have been forced to move into longhouses and start planting fruit trees rather than exclusively forage and hunt. Having been smuggled across the border through a swamp, Parry remeets people who remember him with fondness and he is surprised to find them wearing watches and gazing at television sets as the outside world intrudes upon their ancestral home. He is saddened that the Penan have become part of the consumer boom that is decimating their environment because they have such an innate understanding of and respect for their surroundings.

As he mingles with them, Parry is touched by their readiness to share and revels in the sense of tranquility. But they express their fears about the logging companies exceeding their quotas and the pipeline that could pollute their water. Yet, some things never change, as they still rely on the flight of a bird to let them know what certain fruit are ripe and still go on mass hunting expeditions, with the women and children tagging along and sleeping in temporary shelters while the men go in search of wild boar. Parry joins Arau and is enthralled by his concentration while poised with his blowpipe and listening for telltale signs of prey. However, he fears that these skills will be dissipated as agriculture becomes a bigger part of Penan life and ponders the extent to which our evolving way of life has changed humankind as a species.

In order to learn more about focusing on what is important, Parry heads to Allahabad in India to meet the Giri family from Haridwar, who have agreed to take him to the Kumbh Mela, a ritual gathering for cleansing in the Ganges that attracts some of the biggest crowds in recorded history. Mahant Jagadesh Giri, Yogeshwar Giri and Ramanand Giri are Hindu Sadhu aesthetics and they urge Parry to forget what he has read in books in order to clear his mind and attain inner consciousness. However, he is acutely aware of the chatter in his head that is preventing him from concentrating on his body and senses and finds it difficult simply to accept that the heart can discern truth when he has been taught to draw conclusions from observation and analysis.

Parry goes to the Isle of Skye to see experimental psychiatrist Iain McGilchrist, the author of The Master and His Emissary: The Divided Brain and the Making of the Western World. He explains how the left hemisphere of the brain is more intense and focused in a serial manner in its assessment of information, while the right takes a parallel approach and embraces other ideas in reaching conclusions. This leads into a discussion of tawai with Jeffrey and Selapan in Borneo, in which they describe how the forest tells then when foods are in season and provides the shelter for the animals and birds they wish to hunt. They are afraid that loggers will keep taking the biggest trees and that the wildlife on which they depend will disappear forever.

Deeply moved by their empathy with every element of their environment, Parry reflects on McGilchrist's theory that the left side of the brain makes us cocky and convinces us that we can do anything we put our minds to. Parry wonders if this addictive hubristic sensation dates from the time when we began to try and master the land rather than receive and protect its bounty. In order to test the idea, he visits  anthropologists Jerome and Ingrid Lewis, who have devoted themselves to the study of hunter-gatherer groups.

They lament the fact that only a few societies in South-East Asia and Africa remain committed to sharing what the land offers and blame Neolithic man for domesticating animals and sewing crops, as this introduced the potentially suicidal concept of property and competition into human civilisation. Jerome reveals that avoiding hierarchies has become hard work, but our ancestors achieved an egalitarianism that the Penan exhibit and he notes that it is no surprise that they are among the most peaceful peoples on the planet.

During his stay, Parry watched a pair of elderly women, Ubong and Kulat, supervising the division of meat and he notes that an inability to store means that they take only what they need for one day. He also deduces that they take pleasure in caring for each other and regrets that transactions in a cash-based society can never be as holistic. McGilchrist puts this down to the left side of the brain blundering along in its assumed rectitude, while the right side is trying to take information, contextualise it and reintegrate it into a beneficial whole.

The Giris claim we have an innate wisdom beneath our layers of conditioning and that we should strip away the inessentials to know ourselves and seek the light of truth that animals and plants know all about, but which humans have forgotten about. They explain the interconnectedness of things and Parry sees a similarity in the way the Penan operate. But he suspects that they may be losing their old beliefs and it's noticeable that an old man named Moyong is shushed when he begins to tell Parry that the younger generation no longer believe in ghosts, spirits and omens.

Parry reflects on the old school lesson that the beliefs of indigenous tribes are mostly baseless superstitions and decides to visit the Pirahã on the Upper Maici River in the Amazon rainforest. They supposedly focus so intently on the here and now that their language has no past or future tense and he wonders how they learn from history or plan for tomorrow. He goes hunting with Apabisi and Toibaiti and they tell him about the spirit of Kaoáíbógí, which guides them in all things from finding food to taking wood for dwellings and fires. They claim that they let Kaoáíbógí protect and instruct them and Parry wonders whether this trust is akin to the innate belief in the truth the Sadhus have.

When sharing with them, he feels a tranquility similar to the one he experienced with the Penan. But, while the Pirahã have resisted the consumer temptations that have seduced neighbouring tribes, they have also been driven to cut down trees in order to plant crops and some of the villagers believe that Kaoáíbógí is angry with them for depleting their resources and Parry bemoans the fact that the vast majority of humanity has ceased to listen to what the natural world is trying to tell us.

As he prepares to bather in the Ganges, he wonders if meditation was invented as a means of creating the silence that might allow us to hear our surroundings speak to us. He speculates about the extent to which religion can reconnect us and Gilchrist opines that the right side of the brain is more inclined towards meditation, while the left seeks thrills. The right hemisphere is also more receptive to music, art and poetry and we should cherish it because the moment we first experience such sensations (before we start to rationalise them) is precious, as are the impulses that the right side of the brain picks up from the heart.

As aerial shots show the vastness of the gathering, Parry joins the throng at the Kumbh Mela and has an epiphanal moment, as he feels a powerful sense of common humanity with everyone else (who are all male) rushing towards the water. But he also felt at one with the river and the clouds and this awareness of being a separate part of a whole gave him a greater appreciation of his place in the world. As a consequence, he felt better able to recognise the impact that his actions have on the rest of humanity and on nature.

Walking up a hill, McGilchrist and Parry discuss the tyranny of empiricism and blame the left-hand side of the brain for discarding ancient ideals that may well contain more than a kernel of truth. Over images of the Penan living in simple harmony, Parry declares that he has discovered a new way to envision himself within the context of humanity and nature. Trekking out with Leyon to see the trench that has been dug for the pipeline, Parry says it would be easy to blame governments and conglomerate for the problems facing the Penan. But his own lifestyle choices have contributed to a jungle that once teemed with life being barren and polluted.

Witnessing the impact of human intrusion into what was once total seclusion, Parry concludes that if we are to save the world, we need to take responsibility for our part in its destruction. He suggests that we can only do this by re-balancing our inner selves and finding empathy beyond our family and friends to other peoples and species because if we are to save ourselves and pass the planet on to future generations, we need to feel the pain that makes change imperative.

The closing image of the pipeline trench running like a livid orange scar through the lush green landscape will leave a deeper impression with many viewers than the high-minded pronouncements crafted by Parry and his team of writers for the frequently florid voiceover. The eloquence of McGilchrist and the Lewises also feels strained beside the wise words of the Penan, the Sadhus and the Pirahã. But this has less to do with the significance of their input than the clumsy way in which Parry and his fellow scribes integrate their ideas into the somewhat superficial central thesis.  

Yet, there's no denying the attractiveness of an increased awareness of the interconnectivity of earthly existence and if Parry persuades one person to rethink their lifestyle then this often deeply moving picture has to be considered a success. Parry himself is a genial and respectful travelling companion, while Ó Fearghail has a remarkable eye for a telling shot. Nicolas Jolliet's aerial and timelapse sequences are also striking, as are the sounds captured by Daniel Hewitt and Pablo Villegas. But Nick Barber's score complements them ably without being overly generic.