Celebrated on April 22, Earth Day reminds people to care for and protect the world in which we live.

The history of Earth Day spans more than four decades. In the early 1960s, U.S. Senator Gaylord Nelson became concerned about the environment. He knew that pollution was a growing problem. He saw plants and animals getting sick and even dying because of the way people were treating the earth.

Nelson wondered why more people did not share his concerns. He began to talk to his fellow congressmen and even the U.S. President about the problems he saw. Nelson knew, though, that talking about the problems was not enough. He wanted to see them solved. Solving the problems, Nelson realized, would require help from millions of people -- not just a few lawmakers. But before he could get people to help, Nelson knew he had to find a way to make them aware of the problems. Then, he had an idea.

Nelson proposed that a special day be set aside to teach people more about the world in which they lived and what they could do to help clean it up. He wrote letters to schools, colleges, and universities across the nation. He also wrote articles for newspapers and magazines.

On April 22, 1970, school children, teenagers, college students and adults across the United States celebrated the first Earth Day. People from all over the country promised to help take card of the environment. In the years since, Earth Day has became an international observance. People all over the world have recognized that the planet needs their help, and they are working to make Earth a safer, cleaner place.