'There's one place on one of the lower levels with this huge giant squid. I literally had this dream most of my childhood - of sketching, and, doofus that I am, not hearing the museum had closed, and then putting the sketch pad down and looking around and the lights are out. It's closed.

'I would go to the 77th Street exit, to get to my house. I would start to run to the 81st Street entrance, and I would pass under the ceiling where the giant squid was supposed to be hanging and it wasn't there. And I'd wake up,' he says.

In The Relic, Hyams brings that childhood terror to life with a monster far more frightening than a mere giant squid. The film follows a detective (Tom Sizemore) who joins forces with an evolutionary biologist (Penelope Ann Miller) to investigate a series of gruesome murders in a natural history museum. The killings seem to be linked to the legend of the Kothoga, a devil-god of the Amazon jungle - a legend which proves to have an all-too-real basis in fact.

The Relic 's museum is indeed a nightmarish setting. Early scenes take us to 'maceration tanks' and bins of flesh-eating beetles that strip animal skeletons, and to the enormous storage rooms that hold uncounted specimen jars. Beneath the exhibition halls, the heroes encounter a bewildering maze of unmapped tunnels.

It seems surreal, but author Douglas Preston insists it is no exaggeration. 'The American Museum is probably the most terrifying structure that exists,' says Preston, an evolutionary biologist and author of several non-fiction books. 'First of all, there are thousands of rooms. I mean, this museum is 25 acres [10 hectares]. It's incredible. Nobody knows how many rooms there are.

'The . . . museum portrayed in both the movie and the book is completely accurate. People have no idea. There are sub-basements and sub-sub-basements and flooded passageways, and rooms that have been walled off.

'There's a room at the museum in New York with these huge crates with Mongolian script all over them, which have never been opened. They're dinosaurs that were found in Outer Mongolia in the early 1920s, shipped back, and they never opened the crates,' Preston says.

Visitors are familiar with displays of dinosaur bones, wildlife, and cultural artifacts, but museums display only a tiny fraction of their collections, about three to five per cent. 'You have never seen the stuff that's in that museum,' he says. 'They've collections of whale eyeballs. They've the intestine of a mastodon in a big glass box of formaldehyde. There are whole animals completely preserved in alcohol. Incredible stuff. The dinosaur bone storage room has bones stacked like cordwood to the ceiling. They actually had to build a building that was specially reinforced to carry the weight of thousands and thousands of tonnes of these fossilised bones.' Ironically, though, when it came time to film Preston's book, the museum that had inspired him turned the producers away. 'I shouldn't be telling you this,' he admits. '[The novel] presents a very unflattering portrait of the administration of the American Museum of Natural History. Obviously, there are no real people in it, but I worked in the museum for 10 years and it's a very accurate portrait. They were outraged by the book.

'Paramount came to the museum and offered them seven figures to film in the museum . . . They pretty much booted them out the door and said, 'We don't want this film in our museum. It's too frightening, it's too horrifying. Children come to our museum and they won't come after they see this terrible film.' ' For Hyams, missing out on the chance to film in his old neighbourhood was a bitter pill. 'I was very disappointed because my mom still lives there, and I wanted to bring the film company and the trucks to 77th Street.' The museum's decision also left the film-makers with a problem. 'Probably there are only really three museums where this could have been done: The New York Museum, the Field Museum [in Chicago] and the Smithsonian [Washington, DC],' Preston says.

Fortunately, the administration of the Field Museum 'loved it. That's a much more relaxed and fun museum. The people there realise, 'Hey, it's a film. No one's really going to think there's a monster roaming the halls of the museum'. They were much more co-operative.' Even Hyams was eventually happy with the move. 'The Field Museum is so beautiful, and the atrium is so much better, visually, than the Museum of Natural History, which doesn't really have a glorious atrium. In terms of this film it probably worked out better.' With the museum in place, Hyams' nightmare still needed a monster. Oscar-winning effects master Stan Winston (The Terminator ) was hired to create the creature even before Hyams came on board to direct. One of Hyams' first tasks was to review Winston's early drawings.

'He had done some amazing stuff. The only real contribution I made was, after looking at some of the stuff Stan had done, I said 'Stan, you've created these extraordinary looking beasts, these amazing, phenomenal and ferocious looking beasts. However, if you're alone in a room with a tiger, it's frightening, because you know you're going to die, but the tiger's beautiful. There's a beauty in some of these beasts. I want something hideous.' Hyams pointed Winston towards certain invertebrates for inspiration, but not to that giant squid. 'We began to talk about the fact that since this is about DNA run amok, it should be reptilian, mammalian, and also, when you start looking at insect features, when they're large, they frighten me. They're hideous. Stan came up with this arachnoid outline for the face, which I thought was just wonderful, because that, to me, is disgusting.'