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. It is one of the few places in Colorado where you can see white-tailed and mule deer. During the summer, when the sunflowers and other wildflowers are in full bloom, deer will wonder through the meadows munching on the tasty flowers.