On August 15, 1969, the Woodstock music festival opens on a patch of farmland in White Lake, a hamlet in the upstate New York town of Bethel.

Promoters John Roberts, Joel Rosenman, Artie Kornfield and Michael Lang originally envisioned the festival as a way to raise funds to build a recording studio and rock-and-roll retreat near the town of Woodstock, New York. The longtime artists’ colony was already a home base for Bob Dylan and other musicians. Despite their relative inexperience, the young promoters managed to sign a roster of top acts, including the Jefferson Airplane, the Who, the Grateful Dead, Sly and the Family Stone, Janis Joplin, Jimi Hendrix, Creedence Clearwater Revival and many more.

Plans for the festival were on the verge of foundering, however, after both Woodstock and the nearby town of Wallkill denied permission to hold the event. Dairy farmer Max Yasgur came to the rescue at the last minute, giving the promoters access to his 600 acres of land in Bethel, some 50 miles from Woodstock.

Early estimates of attendance increased from 50,000 to around 200,000, but by the time the gates opened on Friday, August 15, more than 400,000 people were clamoring to get in. Those without tickets simply walked through gaps in the fences, and the organizers were eventually forced to make the event free of charge. Folk singer and guitarist Richie Havens kicked off the event with a long set, and Joan Baez and Arlo Guthrie also performed on Friday night.

Though Woodstock had left its promoters nearly bankrupt, their ownership of the film and recording rights more than compensated for the losses after the release of a hit documentary film in 1970. Later music festivals inspired by Woodstock’s success failed to live up to its standard, and the festival still stands for many as an example of America’s 1960s youth counterculture at its best.