The environment’s low profile frustrated U.S. Senator Gaylord Nelson of Wisconsin, whose campaigns to protect it during the 1960s had fallen flat.
In 1969 Nelson hit on the idea of an environmental protest modeled after anti-Vietnam War teach-ins.
“It took off like gangbusters. Telegrams, letters, and telephone inquiries poured in from all across the country,” Nelson recounted in an essay shortly before he died in July 2005 at 89. “The American people finally had a forum to express its concern about what was happening to the land, rivers, lakes, and air—and they did so with spectacular exuberance.” (Related: “Earth Day Pictures: 20 Stunning Shots of Earth From Space.”)
Nelson recruited activist Denis Hayes to organize the April 22, 1970, teach-in, which today is sometimes credited with launching the modern environmental movement.
By the end of 1970, the U.S. Environmental Protection Agency had been established, and efforts to improve air and water quality were gaining political traction.