Larry Zupan, Mark Hunter, and Peter Pizzitola join in a group chant in New York's Central Park in June 1967.

Left: A woman sits on a blanket in the grass during the Monterey Pop Festival in Monterey, California, in June 1967. Right: A flower child practices yoga during the the Monterey Pop Festival.

A woman dances in the sun at the KFRC Fantasy Fair and Magic Mountain Music Festival, held at the summit of Mount Tamalpais near San Francisco in early June 1967.

Left: A hippie enjoys the California sunshine in Los Angeles. Right: Hippies gather at Elysian Park in Los Angeles for a love-in celebration of peace and love.

George Harrison listens as Ravi Shankar plays the sitar. During the photo shoot, Harrison said he was studying the sitar under Shankar because he believed Indian music could be a vessel for God's presence.

Left: A man wears flowers in his hair at a love-in held on the grounds of Woburn Abbey in England, in August 1967. Right: A group of hippies participate in a sit-in to legalize marijuana in Hyde Park, London.

Hippies gather for a love-in at Elysian Park in Los Angeles.

American political and social activists Abbie Hoffman and Anita Kushner sit on either side of Linn House, a self-ordained priest of the Neo-American Church, as he performs their wedding ceremony in New York's Central Park in June 1967.

A nomadic hippie sleeps in front of Toronto's City Hall as his pet skunk sniffs at his face.

A group of hippies hang out during the Monterey Pop Festival.

A woman has her face painted by a hippie friend in New York's Greenwich Village.

Left: A young girl attends a hippie event in New York's Central Park. Right: In Chicago, a woman with flowers painted on her face participates in what she called a "be-in" alongside 3,000 other attendees on May 15, 1967.

Young men burn their government-issued draft cards during an anti-Vietnam War protest march in Washington, DC, in 1967.

Approximately 70,000 demonstrators join in the "Levitate the Pentagon" march in Washington, DC, in 1967.

A nude man bathes in the San Francisco Civic Center Plaza fountain, as a crowd of 12,500 peace marchers converged to protest the draft and the Vietnam War. He later managed to escape when police gave chase.

The Beatles pose during the press launch for their new album, Sgt. Pepper's Lonely Hearts Club Band, on May 19, 1967.

Left: Singer Janis Joplin performs in 1967. Right: A hippie dances at a summer solstice celebration at Golden Gate Park in San Francisco.

People dance at a Grateful Dead performance at the Fillmore Auditorium in San Francisco in early summer 1967.

A group of hippies experimenting with psychedelic drugs amuse themselves with bubbles outside London's UFO Club in 1967.