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.
The first Earth Day family 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. More importantly, it "brought 20 million Americans out into the spring sunshine for peaceful demonstrations in favor of environmental reform."
It now is observed in 192 countries, and coordinated by the nonprofit Earth Day Network, chaired by the first Earth Day 1970 organizer Denis Hayes, according to whom Earth Day is now "the largest secular holiday in the world, celebrated by more than a billion people every year." Environmental groups have sought to make Earth Day into a day of action which changes human behavior and provokes policy changes.