Big Southern Butte

Big Southern Butte is the largest and youngest (300,000 years old) of three rhyolitic domes formed over a million years near the center of the Eastern Snake River Plain in the U.S. state of Idaho. In fact, it is one of the largest volcanic domes on earth.^[3] It rises approximately 2500 vertical feet (762 m) above the lava plain in southern Butte County, east of Craters of the Moon National Monument.

• http://en.wikipedia.org/wiki/Big Southern Butte