This image was taken looking out over the rim of the Grand Canyon of the Yellowstone, near Inspiration Point. The Grand Canyon of the Yellowstone today owes much of its current appearance to the melting of glaciers throughout the region, about 10,000 years ago. The meltwater from those glaciers flooded the region, and in doing so formed lakes and rivers that over time carved the canyon.
The geology of the entire Yellowstone region is complex and shaped by a series of huge volcanic eruptions followed by frequent smaller scale geothermal activity such as lava flows. The most recent large-scale eruption in Yellowstone occurred about 600,000 years ago. The blast from this eruption left a collapsed caldera 30 miles wide, 45 miles long, and several thousand feet deep. Over time, lava flows filled the caldera, one such lava flow known as the Canyon Rhyolite flow brought lava to the point of the west end of today's Grand Canyon of the Yellowstone.