Earth Day is an annual event, celebrated on April 22, on which events are held worldwide to demonstrate support for environmental protection. It was first celebrated in 1970, and is now coordinated globally by the Earth Day Network, and celebrated in more than 192 countries each year.

In 1969 at a UNESCO Conference in San Francisco, peace activist John McConnell proposed a day to honor the Earth and the concept of peace, to first be celebrated on March 21, 1970, the first day of spring in the northern hemisphere. This day of nature’s equipoise was later sanctioned in a Proclamation written by McConnell and signed by Secretary General U Thant at the United Nations.

A month later a separate Earth Day was founded by United States Senator Gaylord Nelson as an environmental teach-in first held on April 22, 1970. Nelson was later awarded the Presidential Medal of Freedom Award in recognition of his work.

While this April 22 Earth Day was focused on the United States, an organization launched by Denis Hayes, who was the original national coordinator in 1970, took it international in 1990 and organized events in 141 nations. Numerous communities celebrate Earth Week, an entire week of activities focused on environmental issues.