From left to right, three of the world's greatest singers, Frank Sinatra (1915 - 1998), Dean Martin (1917 - 1995) and Sammy Davis, Jr (1925 - 1990), circa 1965. (Photo by Terry O'Neill/Iconic Images/Getty Images)
From left to right, three of the world's greatest singers, Frank Sinatra (1915 - 1998), Dean Martin (1917 - 1995) and Sammy Davis, Jr (1925 - 1990), circa 1965. (Photo by Terry O'Neill/Iconic Images/Getty Images)