Unlike many reclaimed, abandoned mines, this Canadian cave system is still just a dangerous maze.

The final resting place for a wealthy Roman family, this tomb might be the best preserved of its kind outside Italy.

Large collection from the 3rd millennium BCE.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Natural history museum displaying a famous taxidermied St. Bernard.

A Civil War Museum with some notable medical antiques.

Self-built house and sculpture park where the creator can still be seen in a glass coffin.

A unique attraction and museum dedicated to exploring iconic roadside structures.

Marking the spot where a conquistador gave up his search for the fabled Seven Cities of Gold.

The world's oldest known salt mine.

Home to Hollywood history and a very special salt crystal.

Bizarre Cavern.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

The world's largest drain sits below the city of Kasukabe, Japan.

An underground city of salt.

A neutrino detector built into the largest man-made underground cavity in the world.

Caves famous for the dragon-slaying saint who lived there.

The bears of Bern have been a city highlight for over 500 years.

A hidden garden of stones engraved with scriptures, a Joseph Smith Sphinx, all carved by one man.

The largest prehistoric ruins south of the Sahara, once a powerful center of international trade.

The remnants of an early American attempt at missile defense.

Three legendary, living albino buffalo roaming their pastures for all to see.

An ocean in the making, in the Ethiopian desert.