According to NPS Norris Geyser Basin is the hottest, oldest, and most dynamic of Yellowstone's thermal areas. The highest temperature yet recorded in any geothermal area in Yellowstone was measured in a scientific drill hole at Norris: 459°F (237°C) just 1,087 feet (326 meters) below the surface! On the day that we visited it was misty and rainy - which added to the moodiness for this image.
Yes, yes, of course there's Bison everywhere in the Park. But of course you need to keep your distance, especially with the little ones around.
The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, and it's oh so pretty.