Stanley Kubrick’s 2001: A Space Odyssey debuts in theaters on April 6, in 1968. Kubrick, whose 1964 Cold War satire Dr. Strangelove had been popular with audiences and critics alike, was intrigued by science fiction but felt the genre rarely produced interesting films. He became determined to make one, using the sci-fi story The Sentinel as source material and enlisting its author, Arthur C. Clarke, as his co-writer. The film does feature a coherent plot, involving two scientists and a highly-intelligent computer sent to investigate a mysterious event near Jupiter, but several scenes—including the film’s now-legendary opening, which seems to depict hominids learning to use tools after the appearance of a mysterious monolith—are surreal and highly open to interpretation. Filming required the construction of a giant centrifuge to serve as the spaceship’s interior and numerous expensive visual effects, including a groundbreaking psychedelic sequence near the end of the film so complex that staff referred to it as the “Manhattan Project.” Kubrick is said to have removed over 15 minutes from the final cut, which nonetheless ran well over 2 hours.