Join others in celebrating Earth Day’s 50th anniversary on April 22, 2020. What began as a protest by 20 million Americans in 1970 has become the planet’s largest civic event. This year’s theme is climate action — looking at the challenges and opportunities on the global scale. While Earth Day is usually celebrated with projects and gatherings, this year it will be held online with a digital mobilization effort across social media platforms. Learn more about the history of Earth Day and online opportunities at earthday.org.