The Omen tells the story of an American ambassador (Gregory Peck) who learns his son is the Antichrist.
*Charlton Heston, Roy Scheider, Dick Van Dyke (Dick Van Dyke, really?) and William Holden turned down the lead role. Gregory Peck accepted the lead. William Holden did eventually accept a role in a sequel.
*To make the baboons attack the car in the Windsor Zoo park scene, an official from the zoo was in the back seat of the car with a baby baboon, but the baboons had no response at all. They then took the head of the baboons, and the baboons outside went crazy. Lee Remick's terror as the baboons attack the car was real.
*In the closing scene, Richard Donner used reverse psychology on young Harvey Stephens telling him, "Don't you dare laugh. If you laugh, I won't be your friend." Naturally, Stephens wanted to laugh, and he instead smiled directly into the camera.
*According to at least one biography of Gregory Peck, he took this role at a huge cut in salary (a mere $250,000) but was also guaranteed 10% of the film's box office gross. When it went on to gross more than $60 million in the U.S. alone, The Omen (1976) became the highest-paid performance of Peck's career.