Raunch was firmly on show overnight as London's Barbican cultural centre opened its doors on an exhibition presenting a history of sex in art through the ages."Seduced: Art and Sex from Antiquity to Now" depicts the changing way sexuality has been represented over hundreds of years, from ancient Roman marbles to hard-core modern day photos and videos.Entry to the exhibition, which includes pieces like the 41-minute long Blowjob by Andy Warhol - showing the face of a man as he is orally pleasured - and Ilona on Top by US artist Jeff Koons, is banned for under-18s.The only forbidden items are depictions of rape or paedophilia."We wanted to be bold, to show without having to be careful for the young eyes," said Barbican art gallery head Kate Bush, calling it "one of the most ambitious exhibitions that we've ever done.""It's a journey of 2,500 years of sex through the eyes of the greatest artists," she said.The show, which will open to the public on October 12 and run until January 27, includes some 250 works by more than 70 artists. Over 50,000 visitors are expected to come to the exhibition.The pieces include Roman and Greek objects, murals from Pompeii, Indian manuscripts and Renaissance and Baroque images, as well as Chinese paintings, Japanese engravings and Arabic manuscripts.Well-known mainstream artists are also represented, including erotic drawings from the sketch books of Britain's revolutionary 19th century painter JMW Turner and French sculptor Auguste Rodin.With the invention of photography and video, the artworks became more realist, even raw in the case of American photographer Robert Mapplethorpe. He courted controversy at the end of 1970s with shots showing homosexuals and sado-masochists.Koons's Made In Heaven sculptures - showing he and his wife, former porn star and one-time Italian politician La Cicciolina, making love - and a film by United States artist Nan Goldin also flirt with pornography.The exhibition is "bold but not pornographic," said Martin Kemp, one of its co-curators."It shows how different cultures have dealt, through art, with this very basic, universal human theme: sex," he said."Pornography is uni-dimensional - it does not explore human emotions or relations."The works in the exhibition have come from across the world and, in some cases, have not been displayed before in Britain. Big names featured include Pablo Picasso, Jean-Honore Fragonard, Francis Bacon, Egon Schiele, Gustav Klimt, Rembrandt and Marcel Duchamp.The first item on display is a 50-centimetre plaster fig leaf which was used to hide the private parts of Michelangelo's David from Queen Victoria in the 19th century.The public can also see texts from the Kama Sutra, by the Marquis de Sade and Vladimir Nabokov. Some of the images can be shocking even for modern 21st century sensibilities - all faced censorship when they were originally produced, organisers say."Each of the creations has been censored at some point," said curator Marina Wallace."All is in the degree of acceptability at a certain moment in time," she added.