The Grand Mesa (Civ5)/Civilopedia

The Grand Mesa is a large geologic formation in Colorado, the United States of America. Rising some 5,000 feet above the surrounding territory and with an area of 500 square miles, it is the largest mesa in the world. The Grand Mesa has a layer of volcanic basalt on top, which resists erosion. It did not so much rise into the air, as it remained at its original height as the surrounding terrain was eroded by the action of the Colorado and Gunnison rivers.