The only road through the heart of Glacier National Park.

The fairy tale castle of the "fairy-tale king."

A small but immensely extravagant palace built by the "Night King."

Originally envisioned by King Ludwig II to rival Versailles, Herrenchiemsee's "New Palace" remains half-gilded for lack of funds.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Walk the whole Mississippi River!

Moonbows over Kentucky.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

This museum dedicated to an oft-overlooked support industry features a surprisingly moving brass diorama of a man being saved from a sinking car.

A bizarre roadside attraction and the first instance of miniature golf in the world.

The world's largest private aircraft collection.

A building so large that it has its own weather.

Electrical pylon in the shape of Disney's beloved mouse.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

You thought Santa Claus didn't exist, but it turns out you were wrong.

This huge clock made of flowers and simple machinery was once used a political weapon.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

The massive, original Colgate Clock is mounted on a defunct factory building that was once a prison.

After a water tower painting was accused of being an ad, a simple fix was made that gave the city a motto.

Unique tower has outlasted a takeover of the company.

A pharmacy built in the shape of a mortar and pestle, now resembles a fancy cocktail.

The world's longest known cave system.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.