A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

An eerie, derelict amusement park in Berlin.

This beautiful 19th-century temple stands atop the ruins of its predecessor.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.

These bronze pamphlets remember a remarkable group of Germans who fearlessly opposed the Nazis in the very center of their power.

The patron saint of spinsters grasps a container of dried blood.

Go surfing on this urban wave, "hacked" by local surfers.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

The only museum with its curator—and her pets—buried inside.

This eclectic architectural gem played witness to Zurich’s colonial past.

Vines grow up the metal bars in this public park created from an old machine factory.

Sprawled across the Great Hall ceiling are various constellations and images relating to the zodiac.

A book bound in the skin of an infamous criminal, along with countless other specimens.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

Dive for drinks at Croatia's first and only underwater winery.

The oldest arboretum on the Dalmatian coast doubles as the gardens of Kings Landing in "Game of Thrones."

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

A former factory serves as a shrine to the industry that sustained Santorini for decades.

150 or so scrounged-up lamps, chandeliers, and lanterns light up this alley in central Athens.

The heads and relics of 179 monks slaughtered by pirates are on display within this Ceonobic Monastery.

One of the greatest collections of coins in the world is housed in the former mansion of an archeological pioneer.

These artifacts were discovered during the construction of the airport, with some dating back to the Neolithic period.