Yellowstone National Park

Wyoming/Montana/Idaho

Why you've got to go: It's America's very first national park and has the highest concentration of geysers in the world!

What to do: See Old Faithful, which shoots steam sky-high every 90 minutes, and then move on to the other geysers, stinky mud pots and multi-colored hot springs within walking distance (check out the flower-shaped Morning Glory Pool). Yellowstone is also a great place to spot wildlife: Bison, elk, bears, wolves and Bighorn Sheep all hang out here.

Get there when your kids are: Gradeschoolers

More info: nps.gov/yell