Colorado is home to some remarkably beautiful sandstone formations, as exemplified by the Garden of the Gods Park in Colorado Springs. The park is not large, only 1,367-acres, but has been designated as a National Natural Landmark. It's at the transition of the grasslands of the Great Plains and pinon-juniper woodlands, and is near popular 14,115-foot Pikes Peak.
The park was donated to the city by a private citizen, Mr. Charles Perkins. One of the stipulations is that it remain “free to the entire world.” It still is, and is well worth a visit if you're in the area.