On this day in music history: April 12, 1969 - “Aquarius/Let The Sunshine In ” by The 5th Dimension hits #1 on the Billboard Hot 100 for 6 weeks, also topping the Adult Contemporary chart for 2 weeks on May 10, 1969, and peaking at #6 on the R&B singles chart. Written by Galt MacDermot, James Rado and Gerome Ragni, it is biggest hit for the Los Angeles, CA based pop/R&B vocal quintet. The song is a medley of two songs from the hit Broadway musical “Hair”. The group come to record the song through a twist of fate. Group member Billy Davis, Jr. accidentally leaves his wallet behind in a taxi cab in New York City, it is found by the next fare, who is one of the producers of the musical. He invites the entire group to come to a performance of the show. Enthralled by the musical’s opening song “The Age Of Aquarius” (sung by singer/actor Ronnie Dyson in the original cast), they tell their producer Bones Howe that they want to record it. Howe initially disagrees, feeling that the song sounds “incomplete”. He comes up with the idea of creating a medley using “Aquarius” and the show’s closing number “The Flesh Failures” (subtitled “Let The Sunshine In”). The track is recorded at Wally Heider 3 Studios in Hollywood, CA with members of The Wrecking Crew including Hal Blaine (drums), Joe Osborn (bass),Larry Knechtel (keyboards), Tommy Tesdesco and Mike Deasy (guitars). The 5th Dimension overdub their vocals at United Recording Studios in Las Vegas, NV, while they are playing an engagement at Caesar’s Palace, opening for Frank Sinatra. Released as a single in late February of 1969, the song is an immediate smash. Entering the Hot 100 at #89 on March 8, 1969, it rockets to the top of the chart five weeks later. Coincidentally, “Aquarius” is still sitting at number one when The Cowsills version of the title song “Hair” peaks at #2 (for 2 weeks) behind it on May 10, 1969. The single wins Grammy Awards for Record Of The Year and Best Pop Vocal Performance By A Group in 1970. “Aquarius/Let The Sunshine In” is certified Platinum in the US by the RIAA.