Cities of Stone.

The article offers information on several national parks in the U.S. The Canyon de Chelly National Monument is located across Arizona's eastern border and is a quarter-mile hike to the White House Ruin. The Hovenweep National Monument, on the other hand, is along the Utah-Colorado border and is said to be a centuries-old ghost town. While the Mesa Verde National Park in Colorado is home to the infamous Spruce Tree House, a chiseled architectural marvel. [ABSTRACT FROM PUBLISHER]