There are many things to do in Yellowstone, most of them related to the great outdoors. Many of the activities you can do in a lot of places -- hiking, biking, fishing, boating, horseback riding, sightseeing, picnicking -- but you are doing them in Yellowstone’s incomparable landscape and in one of America’s largest areas of wilderness. That changes things. For example, people catch trout in all kinds of streams. Not many people catch trout within sight of a spouting geyser.