Super-heavy Nazi architectural experiment.

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

This historic stone bridge has an entire neighborhood clinging to its sides.

This classic restaurant features a gorgeous mirror-clad room.

The oldest Jewish cemetery in Europe survived Hitler's Germany.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

The amazing wonder cabinets of a very rich Austrian archbishop.

After a nearly successful attempt on Hitler's life, the conspirators met their fate in the courtyard of this Berlin building.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

This mysterious and once-grand memorial still embodies a remarkable architectural vision.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

This landmark church concealed a crypt packed with bones that was discovered thanks to the London Blitz.

These 17th-century mummies are no longer naturally preserved, but remain on display today.

Italian cave with exceptional acoustics and an unsavory history.

Pompeii's less famous neighbor is still revealing her secrets.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Moss and stone turn this waterfall into an otherworldly liquid veil.

One of the oldest churches in Romania is believed to have been built on the site of a pagan temple.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

This bone-filled cave got its name after they found 140 bear skeletons inside.