While the geysers get the headlines, many Yellowstone visitors leave insisting the park's most beautiful sight is its own canyon. The Grand Canyon of the Yellowstone is a gorge more than twenty miles long, its walls streaked in yellows, oranges, and pinks by the chemical alteration of the volcanic rock.

Two great waterfalls anchor the scene. The Upper Falls and the taller Lower Falls send the Yellowstone River crashing into the canyon, the Lower Falls plunging more than 300 feet, nearly twice the height of Niagara. The roar of the water fills the gorge, and rainbows shimmer in the mist on sunny days.

A network of overlooks and trails lets visitors take in the canyon from every angle. Artist Point offers the classic postcard view down the gorge to the Lower Falls, while steeper trails descend toward the brink for those willing to climb back out.

The colors that give the canyon its name come from iron compounds in the rock, cooked and altered by the same geothermal forces that power the park's geysers. Standing at the rim, with the river thundering below and the painted walls glowing in the light, it is easy to understand why early visitors reached for their paintbrushes and why the sight still stops travelers in their tracks.