Though the Monterey Pop Festival in 1967 came first, Woodstock (pictured) will forever be remembered as the festival that defined a generation. 1969 was the year Richard Nixon took office, Neil Armstrong walked on the moon, and on Aug. 15, 16, and 17, hordes of flower children streamed into a sleepy farm in upstate New York for what billed itself as three days of peace and music. Now, nearly 40 years later and with a rush of new books and an upcoming film about the festival, we look back at what made Woodstock famous — and infamous.