Rocky Mountain Arsenal National Wildlife Refuge

A former Army chemical weapons site converted into an 15,000-acre prairie refuge 15 minutes northeast of Denver. Home to a bison herd, pronghorn, coyotes, and one of the largest wintering bald eagle concentrations near any US metro. The 11-mile Wildlife Drive and 6.5-mile trail system are free; the site's transformation from Superfund to national wildlife refuge is one of the most remarkable environmental reclamation stories in American history.

The 11-mile Wildlife Drive loops through the refuge's restored shortgrass prairie, wetlands, and riparian corridors — the bison herd of approximately 60 animals roams the central prairie units and is frequently visible from the road. The 6.5-mile trail system includes the Lake Ladora loop (a 2.6-mile flat walk around a reservoir) and the Prairie Wind Trail through the core bison habitat. Bald eagles concentrate along the reservoir edges from November through February; golden eagles and prairie falcons hunt the grasslands year-round.

The refuge visitor center presents the full arc of the site's history: Army chemical weapons production from World War II through the Cold War, the 1984 discovery of contamination in Denver's water supply that triggered the Superfund designation, the $2.1 billion cleanup, and the subsequent wildlife recovery. Shell Oil's tank farm formerly operated on the southern portion of the site — the combined chemical and petroleum contamination made this one of the most complex hazardous waste cleanups in US history. The wildlife recovery, especially the bison reintroduction, is the central story.