Mammoth, the world's longest known cave system ... totality of darkness and the miracle of light. Usually on a tour a ranger gathers everyone and, after a warning, switches off the lights.

Mammoth Hot Springs in northern Yellowstone National Park sits on the border of Wyoming and Montana. It is a place you have ...

It is not uncommon to see Park Ranger driving traffic to prevent encounters. When not wandering the streets of Fort Yellowstone, the elk retreat to the bluffs above the Mammoth Hot Springs.