This replica of the Greek structure is in the heart of Nashville.

The world's longest known cave system.

You have to love a museum with a truly dedicated focus. A focus on Superman, for example.

This famous bridge twisted itself into oblivion, but not for the reason you might think.

Scattered throughout London are ancient remnants of the city's former bounding wall.

Roadside collection of 65,000 signs.

A surviving remnant of the thick ice mass that once mantled most of Western Canada's mountains.

Few other hotels can rival the grandeur of the Castle in the Rockies.

The United States Capitol's former columns still stand.

The site of Paul Revere's historic two lantern warning.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

A Texas museum filled with Broncos and Betties.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

The first declared National Monument in the United States.

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

A fitting attraction for the corn capital of the world.