The Grand Canyon of the Yellowstone is the most breathtaking sight inside Yellowstone National Park. Twenty miles long, the canyon is up to 4,000-feet wide and 1,200-feet deep in places. From several vantage points, you can view Lower Falls plunging steeply into the canyon 308 feet, or the Upper Falls tumbling 109 feet. What Created the Grand Canyon of the Yellowstone Pink and Yellow Colors? Pastel colors mark the locations of hot springs and steam vents in the canyon walls. Upwardly percolating fluids have altered the chemistry of the rocks.