Did you know that there are more than 20,000 miles of trails in communities across America that once used to be rail lines? Rails-to-Trails Conservancy is a non-profit organization whose mission it is to create a nationwide network of trails from former rail lines and connecting corridors to build healthier places for healthier people. Learn about the Metropolitan Branch Trail, an 8-mile trail that runs from Union Station in the District of Columbia to Silver Spring in Maryland and that provides a safe and pleasant place for people to walk in an urban environment.