Rocky Mountain Arsenal National Wildlife Refuge, located in Commerce City, Colo., is the largest urban refuge in the National Wildlife System in the U.S. Nowhere else can you get the vastness of open prairie with views of the Front Range and the Denver skyline. And the refuge is loaded with a wide variety of wildlife to boot. The refuge was actually established as a result of the discovery of a nesting pair of bald eagles. Today there is still a nesting pair of eagles along with dozens that visit during the winter months.