Earth Day 2014: How It Became a Global Environmental Event

More than a billion people around the world will celebrate Earth Day on April 22, 2014—the 44th anniversary of the annual day of action.

Earth Day began in 1970, when 20 million people across the United States—that's one in ten—rallied for increased protection of the environment.

"It was really an eye-opening experience for me," Gina McCarthy, the U.S. Environmental Protection Agency administrator, who was a self-described self-centered teenager during the first Earth Day rallies, told National Geographic. (See pictures: "The First Earth Day—Bell-Bottoms and Gas Masks.")

"Not only were people trying to influence decisions on the Vietnam War," she recalled, "but they were beginning to really focus attention on issues like air pollution, the contamination they were seeing in the land, and the need for federal action."

At the time, she said, the environment was in visible ruins—factories legally spewed black clouds of pollutants into the air and dumped toxic waste into streams. (Learn more about air pollution.)

"I can remember the picture of the Cuyahoga River being on fire," she said, referring to the Ohio waterway choked with debris, oil, sludge, industrial wastes, and sewage that spectacularly erupted in flames on June 22, 1969, and caught the nation's attention.

Although members of the public were increasingly incensed at the lack of legal and regulatory mechanisms to thwart environmental pollution, green issues were absent from the U.S. political agenda.

By John Roach

for National Geographic

Read in full here.