drugs including cannabis, peyote, mescaline and LSD began to grow among folk and rock musicians. One of the first musical uses of the term "psychedelic" in the folk scene was by the New York-based folk group The Holy Modal Rounders on their version of Lead Belly's 'Hesitation Blues' in 1964. Folk/avant-garde guitarist John Fahey recorded several songs in the early 1960s experimented with unusual recording techniques, including backwards tapes, and novel instrumental accompaniment including flute and sitar. His nineteen-minute "The Great San Bernardino Birthday Party" "anticipated elements of psychedelia with its nervy improvisations and odd guitar tunings". Similarly, folk guitarist Sandy Bull's early work "incorporated elements of folk, jazz, and Indian and Arabic-influenced dronish modes". His 1963 album Fantasias for Guitar and Banjo explores various styles and "could also be accurately described as one of the very first psychedelic records". Soon musicians began to refer (at first indirectly, and later explicitly) to the drug and attempted to recreate or reflect the experience of taking LSD in their music, just as it was reflected in psychedelic art, literature and film. This trend ran in parallel in both America and Britain and as part of the interconnected folk and rock scenes. As pop music began incorporating psychedelic sounds, the genre emerged as a mainstream and commercial force. Psychedelic rock reached its peak in the last years of the decade. From 1967 to 1968, it was the prevailing sound of rock music, either in the whimsical British variant, or the harder American West Coast acid rock. In America, the 1967 Summer of Love was prefaced by the Human Be-In event and reached its peak at the Monterey Pop Festival. These trends climaxed in the 1969 Woodstock festival, which saw performances by most of the major psychedelic acts, including Jimi Hendrix, Janis Joplin, Jefferson Airplane, and Santana. By the end of the 1960s, the trend of exploring psychedelia in music was largely in retreat. LSD was declared illegal in the US and UK in 1966. The linking of the murders of Sharon Tate and Leno and Rosemary LaBianca by The Manson Family to Beatles songs such as "Helter Skelter" contributed to an anti-hippie backlash. The Altamont Free Concert in California, headlined by The Rolling Stones and Jefferson Airplane on December 6, 1969, did not turn out to be a positive milestone in the psychedelic music scene, as was anticipated; instead, it became notorious for