The brainchild of Senator Gaylord Nelson and inspired by the protests of the 1960s, Earth Day began as a “national teach-in on the environment” and was held on April 22 to maximize the number of students that could be reached on university campuses.

Earth Day, annual celebration honouring the achievements of the environmental movement and raising awareness of the importance of long-term ecological sustainability. Earth Day is celebrated in the United States on April 22; throughout the rest of the world it is celebrated on either April 22 or the day the vernal equinox occurs.