Of Yellowstone that is!
We have been to the Grand Canyon, and also the Little Grand Canyon of Utah - all stunning sites.
This Grand Canyon varies in width from 1500 - 4000 feet, and depths of 750 - 1200 feet. The waterfall on the Yellowstone River flows over 350 feet. There are several parking areas, and trails alongside for miles, making for a great walking/hiking opportunity.
We have had such great weather this trip, not cold, but not so hot that walking is difficult. Perfect in my opinion.