From the NPS's website:

"A “Wonderland of Rocks” is waiting for you to explore at Chiricahua National Monument. This forest of rock spires was eroded from layers of ash deposited by the Turkey Creek Volcano eruption 27 million years ago. The 8 mile paved scenic drive and 18 miles of day-use hiking trails provide opportunities to discover the beauty, natural sounds, and inhabitants of this 11,985 acre site...."
This is a fabulous place to visit, especially if you enjoy hiking and birding.

Set aside as a national monument in 1924 by President Calvin Coolidge, the monument is part of the "Cochise Magic Circle".