Earth Day has its roots in growing concern over pollution in the 1960s, when author Rachel Carson's 1962 book “Silent Spring,” about the pesticide DDT and its damaging effects on the food chain, hit bestseller lists and raised awareness about nature's delicate balance.

Earth Day was founded in 1970 by Senator Gaylord Nelson, with the purpose to inform people about environmental problems that needed to be addressed, according to History. Nelson was inspired by the protests and call to attention to protecting the climate in the 1960s.