Earth Day 2014, April 22

• Earth Day is a celebration with the purpose of inspiring awareness and appreciation of the Earth's natural environment.
• Earth Day was founded by U.S. Senator Gaylord Nelson of Wisconsin having witnessed the effects of massive oil spill in Santa Barbara, California in 1969.
• Earth Day founder Senator Nelson's reasons for choosing April 22 as the celebration's official date was that Earth Day was an “environmental teach-in” to maximize participation of college campuses in the week of April 19–25 which did not fall during exams or spring breaks and there would be less competition with other mid-week events.
• Second reason for choosing the April 22 date was that it did not conflict with religious holidays such as Easter or Passover and was late enough in spring to have decent weather. 
• Third reason for the official date of April 22 is that it is also the anniversary of the birth of noted conservationist John Muir.
• Senator Nelson's partners during that time of inspiration was Republican Congressman Pete McCloskey who acted as co-chair and Denis Hayes who became the national coordinator and who built a national staff composed of 85 personnel.
• Earth Day Network is the global coordinator for Earth Day.
• Originally focused in America, in 1990 Denis Hayes organized another global campaign with 200 million people in 141 countries participating which helped pave the way for the 1992 United Nations Earth Summit in Rio de Janeiro.
• For having founded Earth Day, President Bill Clinton awarded Senator Nelson in 1995 the Presidential Medal of Freedom which is the highest honor given to civilians in the United States.
• In April 22, 2009, Earth Day was renamed as International Mother Earth Day by the United Nations having adopted an official resolution, A/RES/63/278
• April 22, 2014 was the 44th anniversary of Earth Day which has a global theme of "Green Cities".
• In 2014, Earth Day Network dropped Sodastream and spokesmodel Scarlett Johansson in their website's list of sponsors.

NatGeoRun2014 in celebration of Earth Day in the Philippines

References:

Cute-Calendar
EarthTechling
SoftSchools
ChicagoNow
Do Something
About Earth Day Network
Earth Day The History of a Movement
Earth Day Fun Facts
Info Please
Celebrating Earth Day
Earth Day Philippines
Earth Day History and Fun Facts
International Mother Earth Day
Earth Day
Economic Times
The Electronic Intifada
NatGeoRun