Earth Day, celebrated annually on April 22, began in 1970 when millions of people took to the streets to protest the negative impacts of 150 years of industrial development. Earth Day is now a global event as more than 1 billion people in 192 countries take part in the largest civic-focused day of action in the world. Peterson Air Force Base, Colorado, is a part of this celebration, and encourages a focus on plastics and energy reduction within the Air Force theme of: Conserve Today. Secure Tomorrow.