In August 1969, half a million people from all walks of life and every corner of the country converged on a small dairy farm in upstate New York. They came to hear the concert of their lives, but most experienced something far more profound. Celebrate the 50th anniversary of the concert that became a touchstone for a generation, through the voices of those who were present at what became the defining moment of the counterculture revolution.

Watch Woodstock: Three Days that Defined a Generation on WGBH's American Experience, tonight at 9pm on WGBH 2.