Castlewood Canyon holds a genuinely unexpected landscape: a deep sandstone canyon carved by Cherry Creek through the Black Forest, with ponderosa pines, Gambel oaks, and dramatic rock walls that feel nothing like the open plains just miles away. The trail system runs 0.5 to 4 miles, ranging from fully paved, wheelchair-accessible rim trails with canyon overlooks to rugged canyon-floor paths along Cherry Creek. The absolute standout is the ruins of the Castlewood Canyon Dam. In summer, one of the largest turkey vulture populations in Colorado roosts in the canyon, where they are visible from the rim. No camping. Pic: Colorado Parks and Wildlife