Photo credit: Jonsson, Kayt / USFWS

Located in the Denver metropolitan area, the Rocky Mountain Arsenal National Wildlife Refuge provides a sense of refuge to both wildlife and visitors. 

This 15,000 acre site provides 20 miles of easy hiking trails and an 11 mile wildlife drive tour for you to enjoy the natural world around you.  The land on which the Refuge resides has a long history from native groups who lived off the land following large herds of bison, to homesteading, to a chemical weapons manufacturing facility, and now a refuge for native wildlife. Today, it is one of the most studied environmental restoration sites in the country. The Refuge works toward restoring native grasses and plants to provide shelter, food, and nesting materials for the wildlife that call this area home.

https://www.fws.gov/refuge/rocky-mountain-arsenal