Yellowstone National Park is home to a host of geothermal features, one of the strangest of which are the mudpots in the Mud Volcano Area. These pools of roiling mud are some of the most acidic features in the park, with a limited water supply and microorganisms that produce hydrogen sulfide gas and produce a distinctive stench of rotten eggs.
Early explorers called mudpots "most repulsive and terrifying", and the heat and smell would normally be enough to keep people away even without the many warning signs erected by park staff, but some visitors still insist on wandering off the boardwalks and getting perilously close to the stinking, steaming mud.
