The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

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

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Every year, over 25,000 monarchs overwinter in Pacific Grove.

A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

Small ship votives hang from the vaulted ceiling of this port-side church with a Latin inscription on the wall.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

The statue of a legendary giant who carried Christ and shouldered the world's sins.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Opulence and fantasy collide in this royal chair which is supposedly made with unicorn horns.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Copenhagen's celebrated theme park and gardens.

Yugoslavia's biggest underground airport lies in ruins.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

Humble beginnings for one of the world's most famous scientists.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A bit of retro transportation flair preserved in the world's largest department store.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

One man's swirling six-acre monument of stone.