A revolution occurred in 20th century music listening as the radio gained popularity worldwide, and new media and technologies were developed to record, capture, reproduce and distribute music. Because music was no longer limited to concerts and clubs, it became possible for music artists to quickly gain fame nationwide and sometimes worldwide. Conversely, audiences were able to be exposed to a wider range of music than ever before, giving rise to the phenomenon of world music. Music performances became increasingly visual with the broadcast and recording of music videos and concerts. Music of all kinds also became increasingly portable. Headphones allowed people sitting next to each other to listen to entirely different performances or share the same performance. Copyright laws were strengthened, but new technologies also made it easier to record and reproduce copyrighted music illegally.