A trip out to El Malpais National Monument and a special location sited near the Bandera Crater. By Bandera is a small cave depressed into the earth made by the lava flows. The porous lava flow acts as an insulator and allows the cave to never get above 31 degrees, hence preserving the ice throughout the entire year. The deepest ice dates back 3,400 years and is up to 20 feet thick.

http://www.icecaves.com/