Any gathering of 500,000 equals one heck of a party, and that's what went down on a 600-acre dairy farm in Bethel, NY, in 1969. Back then, four young men teamed up to put on the four-day Woodstock Music & Art Fair. Scheduled to begin August 15, the event was planned to showcase the music of 32 leading and emerging performers of the day -- people like Janis Joplin, Jefferson Airplane, Jimi Hendrix, the Grateful Dead and the Who [source: Woodstock].
The music festival looked like it would be a success beforehand; more than 100,000 tickets were sold in advance. But it exploded beyond everyone's expectations as the numbers of attendees quintupled, despite the fact that it poured rain much of the time, turning the farm into an enormous mud pit. Woodstock was a mostly peaceful party. But many of the attendees used recreational drugs, ran around naked and had sex out in the open, which helped propel the festival to its status as one of the iconic events of the turbulent, time-changing 1960s. It's also considered possibly the most pivotal moment in the history of music [sources: Motilo, Woodstock].