The Grand Canyon Caverns is believed to be the largest dry cavern system in the US, and also possible the world (although definitive research about how big it really is hasn?t been completed yet). It is a very rare type of underground area, as most caverns are usually filled with water.

The Grand Canyon Caverns was discovered in 1927, when the discoverer, Walter Peck, almost fell into a hole in the ground that he actually learned later on to be 150 feet deep. The actual area underground is so massive that initial measurement says that three football fields could fit inside it.

Today, visitors can see not only the traces of natural history inside the Grand Canyon Caverns, but they can also find some remnants of the time when the US government used the area during the 1963 Cuban Missile Crisis.