The only structure left with direct ties to the Salem witchcraft trials of 1692.

An enormous, inside-out glass globe built in 1935.

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

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.

This abandoned sea fort has become an accidental bird sanctuary.

A priceless collection of the Nation's cryptologic history.

This free, take-a-book shop seems like a trick but isn't.

Bizarre Cavern.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

A monument marks the beginning of the longest north-south road in the United States.

This massive solar system model is sprawled out across Maine's suburban wilderness.

The most photographed house in Maine looks good enough to eat.

True to its name, this bouncy walkway may be the world’s smallest suspension bridge.

The world's largest rotating world.

This tiny patch of arid sand sits in one of the greenest states in the United States.

The LSU mascot lived on the college campus in one of the most impressive tiger habitats in the country.

One of the longest water bridges in the world was built over a supposedly haunted swamp in Louisiana.

This knobby, drooping New Orleans oak is a favorite place both for climbing and for meeting giraffes.

By day this New Orleans square is for pedestrians, but by night it is a kingdom of kittens.

An enormous natural sandstone bridge in Kentucky.

This modern castle sat empty for decades before a fire inspired its builders to complete its luxury halls.

Prehistoric animals decorate this popular outdoor park.

Moonbows over Kentucky.

The world's longest known cave system.