The United Nations celebrates Earth Day on the March Equinox. The United States celebrates this observation on April 22nd. It is observed to bring attention to global environmental issues.
Regular Websites
Offers information about environmental activism, educational resources and Earth Day events and actions. - Earth Day Network
http://www.earthday.net/
Features the history of Earth Day along with resources for kids, volunteers and activists. - EarthDay.gov
http://www.earthday.gov/
Contains a wide range of nature, butterfly and caterpillar crafts as well as printable worksheets and books. - Enchanted Learning: Earth Day
http://www.enchantedlearning.com/crafts/earthday/