What song by The Doors opens the film 'Apocalypse Now'?

"The End" was used in Francis Ford Coppola's 1979 film Apocalypse Now, both in the opening sequence and during the end.

"The End" is a song by the American rock group, The Doors. Its lyrics were written by the lead singer, Jim Morrison. He originally wrote the song about breaking up with his girlfriend Mary Werbelow, but it evolved through months of performances at Los Angeles' Whisky a Go Go into a nearly 12-minute track on their self-titled debut album. It was first released in January 1967. The song was recorded live in the studio with no overdubbing. Two takes were done and it has been held that the second take is the one that was issued. However, there is also a view that the issued version of the song was an edit of both takes, with at least one splice. The band would perform the song to close their last live performance as a foursome on December 12, 1970, at The Warehouse in New Orleans.