Chiricahua National Monument
The National Parks Service calls Chiricahua National Monument in Arizona a "wonderland of rocks." It's an apt description — the national monument was created in 1924 to protect an extensive number of hoodoos and balancing rocks, like the one pictured here. Some of these rocks rise hundreds of feet into the air and look ready to topple at any time.
About 27 million years ago, a huge volcanic eruption shook this area of southeastern Arizona, depositing a few thousand feet of dark ash and pumice, which eventually eroded into the natural features we see at the monument today.
In 2008, the national monument was added to the National Register of Historic Places. However, not many people visit as this section of the Chiricahua Mountains is difficult to access.