Organizing the first Earth Day, April 22, 1970: "From a small Washington, D.C. office, Environment Teach-In, Inc. organized the first Earth Day as a coordinated teach-in involving several schools across the U.S. Denis Hayes [above, seated, with Judy Moody] ran the small activist group co-founded by Senator Gaylord Nelson. The teach-in was designed to educate Americans about growing problems with environmental pollution and overpopulation."

See more images of the first Earth Day at PBS and National Geographic, and watch The Seeds of a Revolution: Earth Days online at American Experience.

Flat Earth is celebrating Earth Day tomorrow by not driving.