Called the Grand Canyon of the Yellowstone River this canyon has just what it takes to be a wonderful photographic destination. There are steep precipitous cliffs, psychedelic colors, two waterfalls, geothermal features along the edge and more. We focused on the Lower Falls, at 308 feet, which are the largest volume waterfalls in the Rocky Mountains. The waterfall is nearly twice the height of Niagara Falls. The colors along the canyon walls is due to the presence of sulphur and other elements that are found throughout Yellowstone. We made a point of being there about 9:45 in hopes of catching a rainbow at the bottom of the waterfall. We did get to see it but its intensity is not as we hoped and that was most likely due to the cloud cover that kept the sunlight from being its most intense.