Today marks the 45^th anniversary of Earth Day, founded by U.S. Senator Gaylord Nelson as an environmental teach-in. Upon its founding in 1970, it achieved rare political alignment, harnessing support from Republicans and Democrats, as well as from those from all walks of life, leading to the creation of the United States Environmental Protection Agency and the passage of the Clean Air, Clean Water Act and Endangered Species Act. The day marks the anniversary of what many consider the birth of the modern environmental movement.

Two decades later in 1990, a group of environmental leaders called on national coordinator Denis Hayes to organize another big campaign for Earth Day, which culminated into a global fever for environmental advocacy, mobilizing 200 million people in 141 countries and bringing environmental issues into a global spotlight. Earth Day that year brought attention to recycling efforts worldwide and helped pave the road for the 1992 United Nations Earth Summit in Rio de Janeiro. It also prompted President Bill Clinton to award Senator Nelson the Presidential Medal of Freedom — the highest honor given to civilians in the United States — in 1995 for his role as Earth Day founder.

At the turn of the millennium, Hayes spearheaded another campaign, focusing on global warming and a push for clean energy. The campaign brought 5,000 environmental groups in a record 184 countries to reach out to hundreds of millions of people and it used the Internet to organize activists.

Ten years later, Earth Day came with challenges to the environmental community, mainly a disinterested public, deniers of climate change and a divided environmental community. Despite the challenges, Earth Day Network was established for the 40^th anniversary as a focal point around which people could show their commitment.

Since its inception, Earth Day has broadened the base of support for environmental programs, generated public support and establishes community activism around the world through a wide variety of events and activities. As the largest civic event in the world, celebrated simultaneously around the globe, more than one billion people participate in Earth Day campaigns.

So today, join the worldwide initiative — plant a tree, pick an area and sweep it for litter, start a personal campaign to recycle household trash items. The ways to get involved and make the world a cleaner and greener place are endless.