David Crosby at Mount Tam, 1967, participated in the Fantasy Fair and Magic Mountain Music Festival, widely considered the first true rock festival. Held on the slopes of Mount Tamalpais in Marin County, the event predated Monterey Pop by one week and set the template for the outdoor gatherings of the hippie era.
Crosby, appearing with The Byrds, played to a colorful crowd of "flower children" in a natural amphitheater. The vibe was communal and chaotic, establishing the ethos of peace, love, and music that would define the San Francisco sound for the rest of the decade.
While often overshadowed by the larger festivals that followed, Mount Tam was the genesis. Crosby’s presence there placed him at ground zero of the counterculture explosion, bridging the gap between the Los Angeles folk-rock scene and the Bay Area psychedelia.