This "natural" outdoor hot tub would go great with my Japanese garden theme. It is almost like a hot spring. I'd get rid of the ugly fence in the background though and have a lot of flowers, trees, and bushes.
During the Hadean Eon volcanoes played an integral part in the formation of the Earth. Even today volcanoes play a key role in the Earth's continued renewal of itself. Children and adults alike, it seems, are fascinated by these fountains of living.