Sentinel Spire is a freestanding sandstone pillar in Colorado National Monument, rising about 200 feet in Wedding Canyon near Window Rock and Pipe Organ. Formed chiefly of Wingate Sandstone laid down about 200 million years ago when the area was covered by wind-blown dunes, it stands above older Chinle and Precambrian rock layers. Runoff from the formation drains toward the Colorado River. Beyond its geologic prominence, the spire holds an important place in the monument’s climbing history: its summit was first reached on May 3, 1960, and later climbers achieved notable solo and free ascents on routes including Fast Draw, Vision Quest, and Medicine Man.