Steep canyons, a meandering stream, a waterfall, lush vegetation, and considerable wildlife distinguish this 2,000-acre park. You can see the remains of Castlewood Canyon Dam, which was built for irrigation in 1890; it collapsed in 1933, killing two people and flooding the streets of Denver. The park, 30 miles south of Denver on Colo. 83, east of Castle Rock in Franktown, provides picnic facilities and hiking trails.