What Is Earth Day?

Clean energy industries may be a popular thing lately, but there's nothing new about the green movement. Earth Day celebrates its 39th anniversary this week. It's a day set especially to appreciate and raise awareness of the Earth's environment. And this movement has come a long ways since those early days of green living.

On an April day back in 1970, millions came together to voice their desire for a cleaner future. Earth Day began as a nationwide grassroots response to growing environmental concerns. Once a date was set, the news services carried the story across the country. Everyone was invited to participate. And they came out in droves.

Twenty million citizens and thousands of schools and local communities participated on that first earth day. President Richard Nixon responded by creating the environmental protection agency. Dreamed up by Wisconsin Senator Gaylord Nelson, Earth Day events helped spawn the modern environmental movement. And from that, the first federal environmental legislation -- the Clean Air and Clean Water Acts.

Now, Earth Day is observed each year on April 22 by more than 500 million people and governments in 175 countries.