There were some pools missing on certain areas. They say that constant tremors move rocks underground and plug up passages. At the same time new ones will be formed. They also say that Yellowstone sits on the biggest volcano around and that it may someday blow covering the northern hemisphere with a cloud of ash. We felt truly small on that land of giants. We didn’t go on the northeast side where most bears and wolves can be found. Check out Bear Tooth Hwy. If you ever visit the place.