The year 1967 saw the emergence of a diverse range of rock music genres, including psychedelic rock, progressive rock, hard rock, and blues rock. Psychedelic rock, characterized by its use of experimental sounds and drug-inspired lyrics, had gained popularity with several notable releases during the year, including The Beatles’ Sgt. Pepper’s Lonely Hearts Club Band and The Doors’ self-titled debut. Progressive rock, often featuring intricate musical arrangements and complex song structures, was also gaining popularity with releases such as Pink Floyd’s The Piper at the Gates of Dawn and The Moody Blues’ Days of Future Passed. Hard rock, a heavier and more aggressive style of rock, began to emerge with bands such as Cream and The Jimi Hendrix Experience. Meanwhile, blues rock, combining elements of blues and rock music, continued to be popular with bands such as The Rolling Stones and the formation of Led Zeppelin.