We stopped at Mud Volcano and walked the loop trail. We both got half sick from the sulphur smell; it was overpowering. This area contains a lot of boiling, noisy cauldrons. When the first white explorers came to this area, they could hear the pounding from miles away.

Sulphur Cauldron is a couple hundred yards away from Mud Volcano. It has a few boiling cauldrons and springs with a lot of white mineral area around them. The Yellowstone River also has some steam vents in and along it at this point.