Colleen Paige created National Wildlife Day in honor of the late wildlife conservationist Steve Irwin — the famed "Crocodile Hunter."
President Nixon signed a law protecting threatened species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation."
American biologist and conservationist Rachel Carson published "Silent Spring," documenting the adverse effects of pesticides on the environment.
President Ulysses S. Grant signed the law establishing Yellowstone as America's first national park — and the first national park in the world.