There are hit albums, and then there's Dark Side of the Moon. Pink Floyd's eternally popular song cycle has sold more than 15 million copies in the U.S. since its release on March 1st, 1973, and more than 45 million units worldwide. A true colossus of classic rock, the album made its creators –
This article originally appeared on www.rollingstone.com: Pink Floyd’s ‘Dark Side of the Moon’: 10 Things You Didn’t Know