What was the original name of the event that became the first Earth Day?

The event that became the first Earth Day was originally called the National Environmental Teach-In.

Senator Gaylord Nelson first proposed a nationwide environmental teach-in in 1969, borrowing the idea of campus “teach-ins” used to debate the Vietnam War. The plan was intended to bring environmental pollution and public health into classrooms, community meetings, and political discussion across the United States.

Denis Hayes expanded the campaign beyond colleges and helped replace the cumbersome teach-in label with “Earth Day.” Advertising writer Julian Koenig is generally credited with coining the name, which quickly caught on after a promotional advertisement. Nelson initially continued using “Environmental Teach-In,” but eventually accepted the new name.

The first Earth Day was held on April 22, 1970, and drew an estimated 20 million Americans. It helped build momentum for the Environmental Protection Agency and major laws including the Clean Air Act and Clean Water Act. It is distinct from World Environment Day, the United Nations observance held on June 5.