There are some pretty amazing fact behind the classics. See the full selection of films at BBC

Mulholland Drive, number 21
“The movie is a surrealist dreamscape in the form of a Hollywood film noir, and the less sense it makes, the more we can’t stop watching it,” wrote Roger Ebert in his review of Mulholland Drive. “Nothing leads anywhere, and that’s even before the characters start to fracture and recombine like flesh caught in a kaleidoscope. Mulholland Drive isn’t like Memento, where if you watch it closely enough, you can hope to explain the mystery. There is no explanation. There may not even be a mystery.” Director David Lynch has said: “I don't know why people expect art to make sense when they accept the fact that life doesn't make sense.”

Some Like it Hot, number 30
Marilyn Monroe’s contract stipulated that her films had to be shot in colour, but test shots of Tony Curtis and Jack Lemmon in drag were said to be so grotesque that director Billy Wilder opted for black and white. Jerry Lewis turned down Jack Lemmon’s role, later telling Esquire: “I felt I couldn’t bring anything funny to it. The outfit was funny. I don’t need to compete with the wardrobe. So whenever Billy Wilder saw me, he said, ‘Good afternoon, schmuck, how’s it going?’ And, of course, Jack Lemmon sent me candy and roses every holiday, and the card always read: THANKS FOR BEING AN IDIOT.”

Psycho, number 8
Composer Bernard Herrmann once told director Brian De Palma: “I remember sitting in a screening room after seeing the rough cut of Psycho. Hitch was nervously pacing back and forth, saying it was awful… ‘Wait a minute,’ I said, ‘I have some ideas. How about a score completely for strings? I used to be a violin player you know.’” According to Hitchcock’s original notes, “Through the killing, there should be the shower noise and the blows of the knife. We should hear water gurgling down the drain of the bathtub, especially when we go closer it… during the murder, the sound of the shower should be continuous and monotonous, only broken by the screams of Marion.” As Herrmann put it, “He didn't even want any music in the shower scene. Can you imagine that?”