Board Walk Disappears into Steam

A board walk tourists take to view geysers is engulfed in steam in Yellowstone National Park. Yellowstone is the nations first National Park, it spans three states.<br />
The Yellowstone Caldera is the largest volcanic system in North America. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions.<br />
There are 300 geysers in Yellowstone and a total of at least 10,000 geothermal features altogether. Half the geothermal features and two-thirds of the world's geysers are concentrated in Yellowstone.[37]