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 – bassist/vocalist Roger Waters, guitarist/vocalist David Gilmour, keyboardist/vocalist Rick Write and drummer Nick Mason – incredibly wealthy, and ultimately spent a mind-boggling 937 weeks on the Billboard 200.

In addition to its massive commercial success, Dark Side of the Moon was also a career-defining artistic achievement for the British quartet, one which marked Pink Floyd’s transition from an experimental, jam-oriented progressive outfit primarily beloved by college students and assorted “heads,” to a top-echelon rock act characterized by its rich songwriting – as well as by Waters’ mordant worldview.

Click here to learn 10 things you might not know about Dark Side of the Moon.