Stanley Kubrick's celebrated sci-fi treatise uses Strauss' 'Blue Danube', amongst other classical pieces, to add gravity to the film's weightless musings. At the dawn of Mankind, a tribe of ape-like beings are visited on Earth by a large black monolith. Thousands of years later, in the year 2001, scientist Dr Heywood Floyd (William Sylvester) discovers a similar black monolith on the moon, which then emits a signal aimed at the planet Jupiter. A year later, astronauts David Bowman (Keir Dullea) and Frank Poole (Gary Lockwood) are en route to Jupiter to investigate the signal's destination and purpose. However, their mission comes under threat when the ship computer, HAL (voiced by Douglas Rain), seemingly develops a malfunction.