In the very late 1960s and 1970s, rock and roll turned into a harder, louder form of music called rock. In the 1970s, rock music bands played huge, loud concerts in outdoor stadiums. In the early 1970s, many rock bands played psychedelic rock, a type of rock music with lyrics and sounds that were intended to give the listener some idea of what it felt like to be on so-called "mind-expanding" (and usually illegal) drugs, and which some believe even enhanced the experience of being on the drugs themselves. Many bands from Britain played blues music mixed with rock music, such as The Animals, The Kinks, The Who, Jimi Hendrix, the Jeff Beck Group.