NASHVILLE, TN – JUNE 03: Trace Adkins performs at The Grand Ole Opry on June 3, 2014 in Nashville, Tennessee. (Photo by Terry Wyatt/Getty Images for Schmidt Relations)
UNITED KINGDOM – 1st OCTOBER: The Beatles posed with bottles of beer and party snacks and balloons in October 1964. Left to right: Paul McCartney, John Lennon (1940-1980), Ringo Starr and George Harrison (1943-2001). The session was taken to promote the BBC World Service. (Photo by Mark Hayward Archive/Redferns)
LONDON, UNITED KINGDOM – MARCH 06: Nancy Wilson and Ann Wilson of American rock band Heart perform on stage at Wembley Arena on March 6th, 1988 in London, England. (Photo by Pete Still/Redferns)
LONDON – APRIL 20: American singer Glen Campbell performs on stage during "The Glen Campbell Music Show" at BBC Television Centre, London on April 20 1975. (Photo by David Redfern/Redferns)
The Beatles rehearse at the ABC Theatre, Blackpool for the group's bill-topping appearance on ABC TV's Blackpool Night Out, 1 August 1965. Left to right: George Harrison, Paul McCartney, John Lennon, and Ringo Starr. (Photo by Daily Mirror/Daily Mirror/Mirrorpix via Getty Images)
1966: Mama Cass, John Phillips, Denny Doherty, and Michelle Phillips of the rock and roll band "The Mamas And The Papas" pose for a portrait session in a shower for the "If You Can Believe Your Eyes And Ears" album cover which was released in 1966 in Los Angeles. (Photo by Michael Ochs Archives/Getty Images)
