Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

The celebrated eyesore created by starry-eyed sweethearts.

One part antique store, one part curiosities hodge-podge.

The first declared National Monument in the United States.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

An experimental, automotive replica of Stonehenge.

When ecosystems collide in the arid Southwest.

The largest self-built castle in the U.S., six decades in the making.

The highest bridge in America was built for an almost unnervingly small amount of money.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

This hot dog-shaped diner has moved all around Colorado, but has never been to New York.

An annual festival celebrating Colorado's most famous frozen corpse.

The final resting place of American icon Buffalo Bill, and a museum that aids in telling his tale.

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

Once a mortuary that held the remains of Buffalo Bill, this Denver hotspot is now a death-fixated restaurant.

Storage warehouse of the rich and famous.

The "Seinfeld" diner.