Having lived in Houston for a while, I was astounded by the abundance of State Parks so close to the city! Within an hour drive, you can get to awesome crags, beautiful waterfalls, and 14,000 foot peaks - some hiking required.
The parks pictured include Roxborough, Chatfield, Cherry Creek, Staunton, Golden Gate, and Eldorado Canyon. I only visited about half of Denver's State Parks, and of those I visited I only hiked about a dozen miles from each. Some offer over a hundred miles of trail! It's hard to imagine hiking all the state parks near Denver. I only wish I had more time to explore.