The hidden lair of an alchemist rediscovered in a 2002 flood.

Macabre astrological automaton clock dating to the late 1400s.

Two stunning 17th-century libraries and a cabinet of curiosities.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Tucked away inside this concrete building is a church and its grand display of brutalist architecture.

A Spanish artist builds his own castle.

Explore a uniquely pristine Borneo forest, now protected by former headhunters turned tour guides.

Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

This insurance company building reminds customers that witches, bears, and gnomes are out there, best be insured.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

The oldest giants in Catalonia are now displayed in a 14th-century Gothic church.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The plague quarantine island home to the alleged "Vampire of Venice."

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

Venice's "Island of the Mad."

An eerie, little-known Neapolitan museum filled with preserved human remains.

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

A subterranean shelter remains intact under a busy Paris railway station.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.