David Bowie’s 1971 surrealist glam-rock anthem is composed of seemingly disparate phrases woven together with the help of double-tracked vocals, pounding piano and a swelling string section that form a bizarre, dreamlike montage. “Sailors fighting in the dance hall,” Bowie sings, but he doesn’t say who the sailors are or why they’re fighting. Later, he muses, “Mickey Mouse has grown up a cow.” Listen to “Life on Mars?” and you’ll have the distinct impression that you’re reading an entry from Bowie’s dream journal. Yet he sings with such yearning and compassion that you find yourself moved by the song even though you’re not quite sure what it’s about. (Maybe that’s why the BBC once likened it to a Salvador Dalí painting.) Further complicating the song is the notion that you’ve heard it before: “Life on Mars?” borrowed a chord sequence from the French song “Comme d’Habitude,” which was later reworked by Paul Anka into “My Way.” So what is this space-age Frank Sinatra send-up about? According to Bowie, it’s a young girl’s reaction to watching the news.