There is a noticeable area of undeveloped land in all that urban growth. Just west of the new airport is open land that is now protected from development.

The former area of farmland and grazing land became a chemical weapons manufacturing facility during World War II. Chemical weapons manufacturing ended in 1969, and Shell Oil Co. began using the facility to produce agricultural chemicals. This continued until 1985.

Referred to as the most contaminated place in America, environmental recovery efforts at the site began in the 1980s and continue today. The area became Rocky Mountain Arsenal National Wildlife Refuge in 1992. The valuable prairie, wetland, and woodland habitat is a sanctuary for bison, deer, bald eagles, owls, and many other species. The refuge reached its current size of 15,000 acres in 2010 and offers visitors fishing, hiking, and wildlife viewing.

USGS aerial photos from 1953 and 1971 show these facilities. Many of the structures are no longer there in recent high-resolution images.