Photo: wisanuboonrawd/iStock

Wyoming: Yellowstone National Park

Yellowstone National Park is one of America's must-see attractions. Come to spot the Old Faithful Geyser, along with the colorful thermal pools and spring. Wildlife spotting opportunities abound, too (think: bears, wolves, elk, and bison). While getting around the park may be challenging due to the crowds, you can opt to hike, bike, or ride horses.