Earth Day is a day that is intended to inspire awareness and appreciation for the Earth's natural environment. During Earth Day, the world encourages everyone to turn off all unwanted lights. Earth Day was founded by uss Gaylord Nelson as an environmental teach-in first held on April 22, 1970. U Thant, the Secretary-General of United Nations at that time, has recognized it. While the first Earth Day focused on the United States, an organization launched by Denis Hayes, who was the original national coordinator in 1970, took it international in 1990 and organized events in 141 nations. It is celebrated in more than 175 countries. Its name and concept was pioneered by John McConnell in 1969 atUNESCO conference in San Francisco.