The Grand Canyon of the Yellowstone River formed thousands of years ago but remains young in geologic time. After Yellowstone’s most recent icecap melted about 14,000 years ago, the Yellowstone River began excavating old rhyolitic lava flows, and with help from wind, rain, and gravity, it is still carving the canyon today. The canyon’s color and texture are also changing as heat and gases from Yellowstone’s volcano move through the rock, transforming it from buff, pink, and grey to golden and ruddy hues and softening it so it is more easily carved. In 1870, Nathaniel P. Langford wrote that from the narrow projecting point called Inspiration Point, two or three miles below the lower fall, he found his best view of the canyon and felt it was impossible to describe the sensation inspired by such a presence, which impressed on him his own littleness, helplessness, exposure to destruction, and inability to comprehend the mighty architecture of nature.