Okay kiddo, so back in the 1960s there was this super popular band called The Beatles. Everyone was really crazy about them, and they had lots of fans all over the world. The word "mania" means being really really excited about something, and that's exactly what people were feeling about The Beatles! So when we say "Beatlemania" we mean the time when everyone was crazy about The Beatles and couldn't get enough of their music and their style! People would scream and cry and faint just because they saw The Beatles in person or heard their music on the radio. It was a really big deal and lots of people still love The Beatles today because of this time in history.