Earth Day is annually celebrated on April 22. Earth Day began in 1970. Its founder, Gaylord Nelson, then a US Senator from Wisconsin, reacted to the aftermath of a 1969 oil spill in Santa Barbara, California, by proposing the idea for a “national teach-in on the environment.” He persuaded Pete McCloskey, a conservation-minded Republican congressman, to serve as his cochair and recruited Denis Hayes as national coordinator.
Hayes built a national staff to promote events across the country. On the first Earth Day, an estimated 20 million Americans participated in coast-to-coast rallies advocating a healthy, sustainable environment. Large numbers of colleges and universities were the sites of organized protests against the deterioration of the environment. The first Earth Day is generally credited with beginning the process that led to the creation of the Environmental Protection Agency and the passage of the Clean Air, Clean Water, and Endangered Species Acts.