About Endangered Species Day: Endangered Species Day is an opportunity for people of all ages to learn about the importance of protecting endangered species and everyday actions they can take to help protect them. Started in 2006 by the United States Congress, Endangered Species Day is a celebration of the nation’s wildlife and wild places. Every year on the third Friday in May (and throughout the month), zoos, aquariums, parks, botanic gardens, wildlife refuges, museums, schools, community centers, conservation groups and other organizations throughout the country hold tours, special speaker presentations, exhibits, children’s activities and more to celebrate Endangered Species Day.