5th Dimension - "AQUARIUS/Let The SUNSHINE In" 1969 "Medley: Aquarius/Let the Sunshine In (The Flesh Failures)" (commonly called "Aquarius/Let the Sunshine In", "The Age of Aquarius" or "Let the Sunshine In") is a medley of two songs written for the 1967 musical Hair by James Rado and Gerome Ragni (lyrics), and Galt MacDermot (music), released as a single by American R&B group The 5th Dimension. The song peaked at number one for six weeks on the US Billboard Hot 100 pop singles chart in the spri