IT’S a Sunday evening, the sun is going down and inside an enormous blue marquee thousands of music-lovers are being treated to one of the most striking, stirring, and surreal spectacles of the summer.

The stage is stacked with a four-storey grid of open fronted boxes, each containing a white-gowned Indian musician — variously banging, blowing or plucking an instrument.

One by one, further boxes are illuminated, as additional artists are brought into the rousing set — their bass beats thundering through the parched grass beneath our feet. Finally, the piece reaches its crescendo, as, to rapturous applause, the last box is lit up, like the final door on a glowing human advent calendar.

The piece, Manganiyar Seduction by theatrical director Roysten Abel, was one of the many highlights of a stellar Womad (World Of Music And Dance) festival, which came to a close on Sunday.

And, like Abel’s box of turbaned Rajasthani treats, the rest of the festival was as much a feast for the eyes as much as the ears.

This year marked the 30th anniversary of the festival created by Peter Gabriel — who was there but, despite hopeful rumours, did not join the festival’s real star — Robert Plant.

The Led Zeppelin singer charmed and thrilled the crowd with gentle banter, jokey asides (at one point accusing Gabriel of cheating at tennis), and some scorching delta blues courtesy of his band Space Shifters. The group’s rousing blend of chunky rock, blues and North African rhythms were accompanied by African griot (musician-poet) Juldeh Camara on a one-stringed fiddle, called a ritti, highlighting, in the process, the links and striking similarities between Saharan roots music and the blues.

The biggest crowd-pleaser was a reimagined version of the Led Zep classic Black Dog — a welcome gift to the thousands of sun-burned and, possibly still hungover, festival-goers who had waited until the festival’s very end for a glimpse of this rock icon — and to feel the hairs on the backs of their necks quiver at the sound of that skyscraping voice. Other great moments were, as usual, too numerous to mention, but the loudest cheers were reserved for Jimmy Cliff’s headlining set on Friday (with classics Many Rivers to Cross and Wild World eliciting wild sing-alongs); Cuban legends Buena Vista Social Club and Nigerian national hero Femi Kuti’s pounding, groove-laden afrobeat — and his posse of gyrating scantily-clad dancers.

There was even more flesh on show during the set by Solomon Islanders Narasarito — who emerged practically in the buff, puffing away on unfeasibly-large panpipes.

More modest was Saturday’s headliner, Algerian rai master Khaled; the North African superstar impressing with his vocal acrobatics. The sophisticated set may have lacked the immediate punch of Femi, or the rhythmic guitar riffs, deep vocals and funky swagger of Kinshasa’s Jupiter and Okwess International (who provided one of Sunday’s highlights) but his soaring voice was as awesome as Plant’s.

It all seemed so deliciously out of place in this most rarefied corner of the Cotswolds — where even the appearance of Prince Harry (in full party mode and sporting a fetching Angry Birds hat) raised little more than a curious eyebrow.

But it was the unknown names — the anonymous artists who had us singing, clapping and dancing way into the night — who made this special anniversary a vintage year, and reminded us once again how far most other festivals have got to go to match Womad’s effortless blend of fun, energy, relaxation and, yes, musical education.