Today is the annual celebration of Earth Day on which events are held worldwide to demonstrate support for environmental protection. It is now coordinated globally by the Earth Day Network, and is celebrated in more than 192 countries every year.
In 1969 at a UNESCO Conference in San Francisco, the holiday was first proposed with a date of March 21, 1970 being put forth as that day corresponded to the first day of spring in the northern hemisphere. 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 and it is this fixed date that is now used for the holiday today.
Senator Nelson selected this date because it did not fall during College exams or spring breaks and moreover that it did not conflict with religious holidays such as Easter or Passover, and was late enough in spring to have decent weather. The first Earth Day had participants and celebrants in two thousand colleges and universities, roughly ten thousand primary and secondary schools, and hundreds of communities across the United States.
While Earth Day was originally 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 initially. According to Hayes, Earth Day is now “the largest secular holiday in the world, celebrated by more than a billion people every year.”