Which event was the prelude to San Francisco's social phenomenon event 'Summer of Love'?

The 'Human Be-In' was an event in San Francisco's Golden Gate Park Polo Field 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 'Human Be-In' focused the key ideas of the 1960s counterculture: personal empowerment, cultural and political decentralization, communal living, ecological awareness, higher consciousness (with the aid of psychedelic drugs), acceptance of illicit psychedelics use, and radical liberal political consciousness.

The hippie movement developed out of disaffected student communities around San Francisco State University, City College and Berkeley and in San Francisco's beat generation poets and jazz hipsters, who also combined a search for intuitive spontaneity with a rejection of "middle-class morality". Allen Ginsberg personified the transition between the beat and hippie generations.