The Tribeca Film Festival has always prided itself on being a New York affair - so what better choice to close the festival than a film featuring rock legend Lou Reed? Reed's work in the experimental rock band The Velvet Underground helped to define 1960s New York as an edgy, artistic, creatively dangerous city unafraid to push the boundaries of art and music. Reed did release an album about New York - called, typically straightforwardly, New York - but Tribeca focused on his take on another wild-style city, 1970s Berlin. Berlin, a concert film shot in New York 18 months ago, documents the first live performance of Reed's once-derided 1973 recording of the same name. Tribeca co-founder Jane Rosenthal seemed overwhelmed when she introduced the film: 'It's been a busy 10 days, but for me, this is the highlight of it all,' she told a full house at the Director's Guild Theatre in Manhattan. What's more, she said, the normally taciturn Reed, along with film director Julian Schnabel, had agreed to do a Q&A session after the movie. Berlin, the record, is an oft-forgotten masterpiece. Released towards the end of 1973, it is based around the loose concept of a couple falling to pieces due to drugs and despair in divided Berlin. It is a story of brutality, doom, despair and love turned to indifference and hate. The music is often gentle and melodic - the delicate beauty of the instrumentation acts as a clever counterpoint to the horror of what's going on in the story. For instance, the fragile music of Caroline Says II is undercut by some disturbing lyrics: 'Caroline says - as she gets up off the floor/ Why is it that you beat me - it isn't any fun.' The song's coda, beloved of Lou Reed fans, has an eerie sense of despair, with the line: 'It's so cold in Alaska' gently repeating over and over. Reed and producer Bob Ezrin had the idea of staging Berlin back in 1973, but the record was so badly received, the idea came to nothing. 'When Berlin first came out it was almost universally derided,' says Ian Fortnam, reviews editor of Britain's popular Classic Rock magazine. 'Reed wasn't the iconic countercultural figure that he's considered now. Much of the popularity that he enjoyed at the time came courtesy of the largely upbeat and innocuous Transformer album. So when he unleashed the lyrically harrowing, musically sophisticated, emotional roller coaster that was Berlin, the dolly-faced glam kids of the early 1970s were appalled. In a time of recession and strikes, people wanted cheering up, not slashed wrists, wailing children and impeccably realised heartbreak.' Flash forward 37 years, to St Ann's Warehouse, a smallish theatre in the gentrified Dumbo neighbourhood of New York City. Reed, Ezrin, and original guitarist Steve Hunter are going to perform the whole of Berlin for the very first time. It's a fully-fledged rock'n'roll resurrection. What's more, the whole thing is being filmed by New York artist/director Julian Schnabel, who has also created a minimalist set for the stage event. As Schnabel's quietly unobtrusive Tribeca documentary shows, the rendition of the classic is note-for-note. Reed is narrator rather than performer, never engaging the audience, and keeping silence between songs. Even the sobs of the children on The Kids - which were allegedly recordings of children crying because the producers told them that their parents had just died - are there. The playing is careful and passionate, and a feeling of degraded doom seeps over the audience as the decadent atmosphere mounts. When Reed sings the tragic line: 'And this is the place where she cut her wrists' from The Bed, the audience is visibly moved. 'Lou had a bad experience with Berlin when it came out,' Schnabel says. 'He was worried about staging it, as he wasn't sure anyone would like it.' Happily, Reed's fears were unfounded. The concert and film have caused Berlin, the music, to be re-evaluated as a rock masterpiece, says Fortnam. 'The Berlin concert tour was utterly superb - it succeeded in accentuating the drama of the piece to a degree that bordered on the unbearable. Fans of Berlin are extremely passionate about it - I know I am - and we were desperate to see Lou Reed vindicated in this way.' Times have changed, too, he says. 'The rock media is now populated by a generation of writers that grew up with Lou Reed as the godfather of punk, after The Velvet Underground's belated embrace as one of the sacred cows of 20th- century art,' Fortnam says. 'Critics, readers and audiences are now ready for Berlin in a way that they weren't back in 1973.'