Inside, ancient treasures. Outside, modern contradictions.

A memorial for an outsider theorist who believed that the planet is actually hollow.

This engineering marvel is the longest bridge in Canada and one of the longest spans in the world.

An early-19th-century hotel with a past that is steeped in the Civil War.

This shallow cave got its name from copious amount of human bones found inside.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

A life-sized recreation of the megafauna that once roamed this region is a feature at the birthplace of American paleontology.

A miniature world of concrete and stone in Springfield, Ohio.

The childhood home of the Wright Brothers in Dayton.

An abandoned munitions factory with a shot tower continues to wage war on the surrounding environment.

Giant trolls run this farm!

Giant instrument-shaped home in Fayetteville, Georgia.

A vision of beautiful Hindu architecture in the middle of the American South.

This Art-Deco movie palace is the oldest independent cinema in Atlanta.

If all members were present at the table, a sixth of the world's wealth would be under the same roof.

Carved faces add a touch of magic to this island's impressive oak trees.

This vast kitty-themed collection illustrates the history of human-cat interaction.

Enormous lake at the bottom of a unique cave system.

Rare recess caves fill this unbelievably beautiful Ohio park.

Circleville is seriously smitten with this giant gourd.

Where beautiful signs live on forever.

The largest Jewish museum in the southeastern U.S. houses a permanent Holocaust exhibit emphasizing the strength of its survivors.

The world's largest set of the ten commandments lay nestled in the heart of the Great Smoky Mountains.

This collection of ferns from across the globe is the largest assortment in the United States.