Students march through the business district of suburban St. Louis on April 22, 1970, protesting against smog caused by automobiles.
Compared to protests about racial inequality or the Vietnam War, the environment at the time was seen as a neutral cause that everyone could get behind — so much so that the original Earth Day was proposed by a US senator who worked with ecology professor Morton Hilbert and activist Denis Hayes to put it all together.
There wasn't another Earth Day celebration until 1990, and it didn't become an annual event until 2000. While climate change was not yet a major topic at the original Earth Day, some of the demands for sustainable energy and more careful consumption are in line with the student-led climate marches of 2019, which drew millions of schoolchildren to the streets.
Alameda High School students stack up recyclable waste material they had collected in scavenger hunts in connection with an Earth Day observance/teach-in Denver, April 22, 1970.Children use push brooms to sweep a city park during the first Earth Day in New York City.Left: Students build a"world" of tin cans at Regis College in Weston, Massachusetts for Earth Day, April 21, 1970.