Mammoth Hot Springs: Yellowstone National Park

Yellowstone National Park, the first national park in the world, has a plethora of thermal features that steam and bubble as you walk around the built paths. In this photo are the travertine domes that make up part of the Mammoth Hot Springs, a slowly building, living sculpture that changes as more travertine is deposited and more bacteria make the domes their home, adding color to the otherwise bland rock.