English rock group regarded as the most popular and influential rock formation in history. It was formed in Liverpool in 1960 with a sound rooted in skiffle, beat and 1950s rock and roll. The Beatles were integral to the evolution of rock music into an art form, and to the development of the counterculture of the 1960s. They often incorporated elements of classical music, older pop forms, and unconventional recording techniques in innovative ways, and in later years experimented with a number of musical styles ranging from pop ballads and Indian music to psychedelia and hard rock. The Beatles are the best-selling band in history, with estimated sales of over 800 million records worldwide.