Fires were nothing out of the ordinary on Cleveland’s Cuyahoga River in the 1960s. The city was still a manufacturing hub and the river, which empties into Lake Erie, had long been a dumping place for sewage and industrial waste.

But on June 22, 1969, a spark flared from the train tracks down to the river below, igniting industrial debris floating on the surface of the water. Flames spread across the river, in some places reaching five stories high.

And though it only took about 20 minutes to extinguish the blaze, the not-so-unusual river fire helped create an environmental revolution. Though it initially caught the attention of few Cleveland residents, the Cuyahoga River Fire stoked the rest of the nation’s awareness of the environmental and health threats of river pollution—and fueled a growing movement that culminated in the creation of the Environmental Protection Agency.