Rocky Flats National Wildlife Refuge spans 5,237 acres on Colorado’s Front Range and preserves prairie, shrubland, and wetland habitat with remarkable biodiversity near a heavily developed region. The land was used by Native Americans, then by ranching families from 1868 until the U.S. Atomic Energy Commission acquired it in 1951 for the Rocky Flats Plant. From 1952 to 1994, the site was a major U.S. nuclear weapons production facility during the Cold War. After environmental and safety concerns, a long Superfund cleanup led to the refuge’s creation on the outer lands. Today it is valued for wildlife yet remains controversial because of its nuclear legacy.