Earth Day proved popular in the United States and around the world. The first April 22 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. More importantly, it "brought 20 million Americans out into the spring sunshine for peaceful demonstrations in favor of environmental reform."
It is now observed in 175 countries, and coordinated by the nonprofit Earth Day Network, according to whom Earth Day is now "the largest secular holiday in the world, celebrated by more than a half 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
