KnowraEarth DayLinked fromLinked fromThe 9 pages that link to Earth Day, each with the reason it gives.All 9Broader topic 3Related 5Compared with 1EnvironmentalismBroader topic: Its first celebration marked the movement’s rapid expansion into mass politics.Environmental protectionBroader topic: Its first observance in 1970 expressed the scale of emerging public concern.AprilBroader topic: Its fixed April date makes the month a platform for environmental events.