Old Faithful & the Yellowstone Caldera

Old Faithful is the best known, but only one of a myriad of geysers in this beautiful national park. The tame geysers and hot pools are, in fact, sitting inside the world's largest volcanic caldera, the site of truly catastrophic eruptions. If Yellowstone erupted again with the force that it did some 600,000 years ago, it would devastate large areas of the US. These days, it is one of the most beautiful parks in the world and one of the most popular.
Apart from the 400 or so geysers, you can see colourful hot springs, bubbling mudpots, sulphur deposits, a spectacular waterfall in a canyon and wildlife including bison, elk, and bear. This is a volcano for everyone, from children to the elderly. During winters, Yellowstone gets extreme weather and many areas are not open. Best times to visit are from late spring to early fall. Summers can be crowded, as this is a very popular park. It is also huge in area, so plan on spending several days and maybe moving lodgings. There are several places to stay in the park, including campgrounds, cabins, and the superb Old Faithful Inn, which is worth seeing even if you cannot afford to stay there.