The lowest point in South Dakota and the source of the Minnesota River.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

This set of three large, volcanic hot springs is a favorite haunt for intrepid divers.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

The smallest country in the world.