I dont understand why the Beatles were so famous

Their music was revolutionary at the time, but there are always a million bands testing the waters. It's something more than that- it has to do with speaking to the sentiments of an entire generation of youth. There have been other bands like that, nirvana for example, that have grown as a pop culture myth, not only due to circumstance and controversy, but due to their ability to encompass an entire generation of cultural trends...whether either band coined said culture is debatable...