Final answer:
The center of the hippie movement in San Francisco during the 1960s was the Haight-Ashbury district, which became a hub for the counterculture's expression of peace, love, and freedom.
Step-by-step explanation:
The center of the hippie movement in San Francisco was a district known as Haight-Ashbury. The Haight-Ashbury district became the symbolic headquarters of the anti-establishment youth or hippie culture during the 1960s. It was a place where the counterculture thrived and expressed its ideals of peace, love, and freedom, rejecting traditional social values and seeking a nonmaterialistic existence closer to nature. This neighborhood demonstrated San Francisco's exceptional commitment to diversity and tolerance, as evidenced by the gay pride flag referenced in another historic district, The Castro, known for its significant LGBTQ community. The hippie movement is also closely associated with the use of psychedelic drugs, communal living, and a strong influence on music and art.