Extending south of Bend from the Deschutes River to 7,987ft Paulina Peak, this US Forest Service-administered preserve embraces lava caves and tubes, pumice and cinder cones, fields of obsidian (black volcanic glass), ancient archeological sites, hiking trails, waterfalls, a forest of stone trees and two crater lakes of remarkable scenic beauty.Established within Deschutes National Forest in 1990, the 55,500-acre national monument comprises the massive Newberry Volcano and lava flows to its northwest. Its most recent eruption occurring 1,300 years ago, this 500sq mi shield volcano (a rounded volcano built up from successive lava flows) is considered dormant, though hot springs still bubble beneath the waters of its lakes. Seven thousand years have passed since the last major activity created Lava Butte and, to the south, divided the crater lakes. Yet even as surface flows crusted over, subterranean rivers of molten lava formed unusual caverns in the volcanic plateau's armor.