Parts of the whitish rock-sheet before you pulsate from the pressure of steam and boiling water beneath them. A number of geysers and other features here have been born suddenly in small hydrothermal explosions. Some features are ephemeral, their activity lasting a few hours, days, or weeks. A few others have become relatively permanent fixtures in the scene.
Did You Know?
Even though the animals of Yellowstone seem tame they are still wild. Feeding the animals is not permitted in any way, and all visitors must keep 100 yards away from wolves and bears, and 25 yards from other animals.