Throughout the summer of 1969, Harlem attracted thousands by assembling some of the best musical talents around for the Harlem Cultural Festival. B.B. King brought the blues, Mahalia Jackson brought the gospel, Jesse Jackson brought the church, and Sly and the Family Stone brought it all together. The concert was free, the theme was community, and the message was clear: Black is beautiful.

The festival was a success, but it quickly faded from public consciousness. One hundred miles north, a similar music festival in Woodstock, New York, took all the headlines. When Hal Tulchin, who filmed the entire Harlem Cultural Festival, tried to sell the reels, he pitched it as the “Black Woodstock” but found no takers. So the footage sat, unseen and unused, for 50 years in a basement. Then, in 2017, producers David Dinerstein and Robert Fyvolent brought the footage to Ahmir “Questlove” Thompson’s attention and asked if he wanted to make a movie with it. Thompson did, and Summer of Soul (…Or, When the Revolution Could Not Be Televised) is the result: A combination of Tulchin’s vérité footage intersperses it with contemporary interviews. It’s a joyous portrait from a less-than joyous time in American history.

Even better, Thompson plays the footage from the concert for those who haven’t seen it for over 50 years. Most are moved to tears, happy to revisit that moment when the neighborhood stopped and celebrated diversity beyond a simple acronym.

Now playing the Sundance Film Festival.