The world's oldest continuously operating airport was founded by the Wright Brothers.

This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

Built by the patriotic residents of Boonsboro in a single day.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

The land is home to swimming ponies and a legendary 18th-century treasure.

The commemorative stone column conceals a secret laboratory.

These unusual rooms on wheels are holdovers from the 1960s.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.

A cablecar-station-turned-revolving restaurant with 360-degree views of the Swiss skyline.

A historic observatory precariously perched at the "Top of Europe."

The alpine falls where Sherlock Holmes apparently met his demise can actually be visited.

This memorial museum chronicles the apocalyptic destruction of the First World War.

Enter the cabin of a life-sized Hindenburg replica.

A Black Forest cuckoo clock theme park features one timepiece big enough to walk inside.

Berlin's old airport.

This statue of the "father of television" stands prominently in the United States Capitol.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

There’s a hidden military meme engraved on the World War II Memorial.