Photo: Earth Day, 1970

90 of 368
April 22 1970 New York City

credit: Frank Castoral

90 of 368

The first Earth Day was held on April 22, 1970. It was a sunny day in New York City, and thousands of New Yorkers marched down 5th Avenue, from Midtown to 14th street. Today, over 1 billion people observe Earth Day around the world, according to The Earth Day Network.

Do you want your photo of the great outdoors featured on TreeHugger? Join the TreeHugger Photo Pool on Flickr and add your photos to the group!