`NorthAmNative}}    Devil's Tower National Monument, Devil's Tower  == Origin ==  Devil's Tower has, indeed, a volcanic origin. It was most likely, a ``caldera`` similar to Kilauea's, without having an external flow and, therefore, without any volcanic material around its crater. Most ``calderas`` have little gases and hot lava may erupt to a certain altitude, but always falling inside the crater. This process explains absence of volcanic debris around Devil's Tower.  `