From their 1969 album "The Age Of Aquarius" en.wikipedia.org "Aquarius/Let the Sunshine In", sometimes incorrectly known as "The Age of Aquarius" or "Let the Sunshine In", is a medley of two songs from the musical Hair ("Aquarius" and "The Flesh Failures (Let The Sunshine In)") written by James Rado, Gerome Ragni and Galt MacDermot, and released as a single in 1969 by The Fifth Dimension. The single held the number one position on the US Billboard Hot 100 for six weeks and was certified Platinum.