"This was a seismic shift in American culture and it gave the teenagers not only a voice but a way of being, a way of thinking that had never occurred before," Beatles biographer Bob Spitz said.
The historic event was the focus of a big celebration in Hollywood Sunday where all four of The Beatles' Walk of Fame stars were decorated with flowers and mementos.
The fun began in front of the Capitol Records building at 12:30 p.m.
Opera singer Shayne Dalva and John Lennon impersonator Tim Piper were set to perform. A special anniversary cake was also be cut by Chris Carter, host of "Breakfast with the Beatles" radio program.
The Associated Press and CNS contributed to this report.