|The rock cycle|
Volcanic eruptions and flowing lava are rather ephemeral phenomena, and it's difficult to plan seeing these. However, a range of other phenomena is more predictable and one can plan to visit these. In geothermal areas groundwater is heated and may appear as hot springs, boiling mud, or under special circumstances as geysers. Yellowstone National Park is full of such marvels, while closer to home the completely volcanic Iceland has also much to offer.
|Hot springs||Hot springs|