Crosby, Stills & Nash is a pioneering folk/rock supergroup formed by David Crosby, Stephen Stills and Graham Nash - refugees from three 1960s bands: The Byrds, Buffalo Springfield, and The Hollies. The band is primarily known for their three-part vocal harmonies. They are strongly associated with the 1969 Woodstock Festival. They are commonly referred to by their initials CSN. The trio's first eponymous album was released in May 1969 and was an immediate hit, spawning two Top 40 hit singles and receiving key airplay on the new FM radio format.