On April 22, 1970, demonstrations across the country took place to mark the first Earth Day. It was unclear back then how many people came together, but historians now think about 20 million Americans took part in gatherings throughout the United States including one of the largest ones in Philadelphia. The day led to legislation and the creation of the Environmental Protection Agency. #EarthDay #1970 #environment #Philadelphia #philly #cronkite #waltercronkite