Started the day at West Thumb Geyser Basin by Yellowstone Lake. It has bubbling mineral pools of various colours, even in the lake. Dozens of cars parked on the roadside meant a bear sighting and sure enough saw a grizzly in the distance. Next onto Mud Volcano and Sulphur Cauldron and LeHardys rapids. Shortly after stopped at a valley full of Bison, some getting very close to the motorhome. Next stop lower and upper falls of the Yellowstone river - fast flowing with an immense volume of snow melt. Then drove on to nearly 9000 feet past Mount Washburn, still with snow on the roadsides, to Tower falls where a black bear was ambling along the car park. Amazing to see! Finally drove 7 miles into the Lamar valley and stopped by views of herds of Bison. Had dinner before the long drive back to the Grant Village campsite and a quick pit stop by Thumb basin again - very atmospheric in the twilight.