This abandoned beacon is moving closer and closer to the sea.

A centuries-old forgotten underworld lies beneath Malta.

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

The medieval home is still engraved with the symbol of the profession, an eye flanked by two axes.

Hidden beneath a restaurant, underground tunnels tell the story of Malta’s tragic role in World War II.

A hidden tunnel of bones in one of Malta's oldest churches.

A rooftop restaurant hides in plain sight atop Vienna's Palace of Justice.

Inside the corridors of this flea market, visitors are sure to find some obscure and odd treasures.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

This former insane asylum now holds a pathological anatomy museum.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

This abandoned office building is a lasting example of Soviet-era architecture.

This little gem in the Gulf of Riga has a very rich heritage and distinct culture.

This is what trains will look like after the zombie apocalypse.

Dummies recreate radiological discoveries from history.

This non-profit theatre in the heart of Brussels is dedicated to hosting independent films.

Medical history with an amazing, if frighting, collection of wax diseases on display.

A visionary precursor to the Internet made of index cards.

The Devil’s own choice when he needs a drink in Brussels.

This massive collection of taxidermy is full of specimens collected by missionaries during their international travels.

Burbling away in refrigerators are 105 sourdough starters from around the world.

This small window display is dedicated to the noble carrot.

An early 20th-century sanatorium, long abandoned and now being reclaimed by nature.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.