The Human Be-In was an event held in San Francisco's Golden Gate Park Polo Fields on January 14, 1967. It was a prelude to San Francisco's Summer of Love, which made the Haight-Ashbury district a symbol of American counterculture and introduced the word "psychedelic" to suburbia.

The counterculture of the 1960s was an anti-establishment cultural phenomenon that developed throughout much of the Western world between the mid-1960s and the mid-1970s. The aggregate movement gained momentum as the U.S. Civil Rights Movement continued to grow, and, with the expansion of the American Government's extensive military intervention in Vietnam, would later become revolutionary to some. As the 1960s progressed, widespread social tensions also developed concerning other issues, and tended to flow along generational lines regarding human sexuality, women's rights, traditional modes of authority, racism, experimentation with psychoactive drugs, and differing interpretations of the American Dream. Many key movements related to these issues were born or advanced within the counterculture of the 1960s.As the era unfolded, what emerged were new cultural forms and a dynamic subculture that celebrated experimentation, modern incarnations of Bohemianism, and the rise of the hippie and other alternative lifestyles. This embrace of creativity is particularly notable in the works of musical acts such as the Beatles and Bob Dylan, as well as of New Hollywood filmmakers, whose works became far less restricted by censorship. Within and across many disciplines, many other creative artists, authors, and thinkers helped define the counterculture movement. Everyday fashion experienced a decline of the suit and especially of the wearing of hats; styles based around jeans, for both men and women, became an important fashion movement that has continued up to the present day.

Several factors distinguished the counterculture of the 1960s from the anti-authoritarian movements of previous eras. The post-World War II baby boom generated an unprecedented number of potentially disaffected youth as prospective participants in a rethinking of the direction of the United States and other democratic societies. Post-war affluence allowed much of the counterculture generation to move beyond the provision of the material necessities of life that had preoccupied their Depression-era parents. The era was also notable in that a significant portion of the array of behaviors and "causes" within the larger movement were quickly assimilated within mainstream society, particularly in the US, even though counterculture participants numbered in the clear minority within their respective national populations.In general, the counterculture era commenced in earnest with the assassination of John F. Kennedy in November 1963; became absorbed into the popular culture with the termination of U.S. combat military involvement in Southeast Asia; and ultimately concluded with the end of the draft in 1973 and the resignation of President Richard Nixon in August 1974.