The Beatles were a pop and rock music group from Liverpool, England, who continue to be held in the very highest regard for their artistic achievements, their huge commercial success, and their ground-breaking role in the history of popular music. Consisting of John Lennon (1940-1980), Paul McCartney (1942-present), George Harrison (1943-2001) and Ringo Starr (1940-present), the group's innovative music and style helped define the 1960s.
The Beatles were, by most definitions, the biggest musical act of the twentieth century. In their homeland alone, they have had more than 40 different singles, albums and EPs reach Number One. This kind of success has been repeated in many more countries and EMI estimated that by 1985, the band had sold over one billion records worldwide.  Their ballad Yesterday, written by McCartney, may well be the most-covered song in the history of recorded music. 
The Beatles' achievements and contributions to popular music, and indeed international youth culture, were profound and wide-ranging. Their early original material fused elements of early American rock 'n roll, pop, and R&B into a new form of popular rock 'n roll, almost single-handedly kick-starting the British Invasion, laying the groundwork for the rock culture of the 1960s, and establishing the prototype for the self-contained rock group.
Throughout their career, The Beatles balanced their huge popularity with increasingly experimental and boundary-pushing music that took cues from eclectic sources like folk, R&B, soul, classical, electronic and Indian music while exploiting increasingly sophisticated technology and innovative recording techniques.
In this way, they helped pioneer more advanced, multi-layered arangements in both rock and pop and were instrumental in the development of some of 1960s rock's dominant styles, such as folk-rock and psychedelia. As songwriters, they were among the most influential and melodically sophisticated of the era, helping to push rock beyond its' early blues and R&B forms and into more expansive territory. Critical evaluation of The Beatles legacy demonstrates that they "introduced more innovations into popular music than any other rock band of the 20th century." 
To a significant extent, however, the impact of The Beatles extended well beyond music. Their clothes, hairstyles, actions, and even choice of instruments made them trend-setters throughout the decade, while their growing social awareness, reflected in the development of their music, saw their influence extend into the social and cultural revolutions of the 1960s. Though the group disbanded in 1970 (amid much internal strife), they are still recognised as easily the most iconic performers of their era, and moreover one of the greatest popular music groups of the entire rock era.