Each year on April 22 the world celebrates Earth Day to recognize what many consider the birth of the modern environmental movement back in 1970.

The goal of Earth Day 2012 is to "Mobilize the Earth." The original idea for Earth Day came from founder Gaylord Nelson who was a U.S. senator from Wisconsin. After witnessing the horrendous damage left behind by the massive 1969oil spill in Santa Barbara, Calif., Nelson decided that it was time to stand up for Mother Earth.

The social causes of the 1960s propelled the activism in the 70s. Protests had taken over the country. The populace was becoming concerned about pollution and other environmental issues.

Nelson was inspired by the movements led by young people and decided if he could infuse the anti-war protests with concern about the environment, the planet would then become an issue that would have to be dealt with on a national level. In 1970, Nelson announced the idea for a "national teach-in on the environment" to the media. He then persuaded Republican Congressman Pete McCloskey and national coordinator Denis Hayes to be a part of his team to change the way the earth was viewed.

Hayes organized a national staff of 85 to promote events across the nation, and on April 22, 1970 the first Earth Day was celebrated. It captured the energy from the anti-war protest movement and put environmental concerns front and center. Approximately 20 million people met in the streets, parks and auditoriums for a demonstration calling for a healthy, suitable living environment. Colleges and universities from coast to coast organized protests against the deterioration of the environment.

Earth Day 1970 also brought about a rare political alignment gaining support from both Republicans and Democrats. The first Earth Day led to the creation of the United States Environmental Protection Agency and the passage of Endangered Species, Clean Air and Clean Water Acts.

In the 1990s, Hayes was asked to organize another big campaign taking Earth Day global. More than 200 million people in 141 countries celebrated Earth Day that year bringing environmental issues onto the world's political agenda and teaching people the benefits of recycling. In 1995, Nelson was awarded the Presidential Medal of Freedom from President Bill Clinton for his role as Earth Day's founder.