On the edge of Denver and Commerce City, Rocky Mountain Arsenal National Wildlife Refuge transformed a former chemical weapons and industrial complex into one of the region’s largest wildlife preserves. Built in 1942 for World War II chemical weapons production, the site later hosted petroleum, pesticide, and chemical manufacturing before closing in 1985. Severe pollution led to federal cleanup, but discoveries of bald eagles and a surprisingly rich animal community helped redirect the land’s future. Congress authorized a refuge in 1992, and land opened in stages beginning in 2004. Today it supports more than 330 wildlife species and symbolizes dramatic ecological recovery.

Commerce City, Colorado · USA