The very first Earth Day was celebrated on April 22, 1970. About 20 million Americans joined rallies, cleanups and teach-ins across the country. Just a few months later, in July 1970, the U.S. government responded by establishing the Environmental Protection Agency.

It’s spring and temperatures are rising; snow is melting and sunshine lingers well into the evening. Millions of birds are returning from their wintering grounds. Soon frogs will sing and

For the 55th year, the world is using the day to celebrate Mother Nature and the wonderful planet we live on. "Earth Day really is a symbol of the environmental movement," Sarah Davies, the director of communications and media at EarthDay.