On Sunday, April 22, more than a billion people around the world will celebrate Earth Day by participating in neighborhood clean-up efforts. The grassroots movement began in 1970 when twenty million Americans took to the streets to voice their concern about the deteriorating environment and to urge lawmakers to take action before it was too late. Now boasting over 50,000 partners in 195 countries, the Earth Day Network (EDN) is credited with instigating many of our current environmental policies, including the Clean Air Act, Clean Water Act, and Endangered Species Act.