Yellowstone National Park
Yellowstone National Park... OMG! I remember as a kid having a 3D Viewer with slides of Old Faithful, which I always wanted to see in person. The Park is huge. From the East Gate it's a 55 mile drive to Old Faithful AND it's an additional 50 mile drive from Cody Wyoming to the East Gate. So, be prepared to drive. The Park attractions are unbelievable and fall under the "You have to see them in person, because photos fail to do them justice!"