A futuristic, brutalist masterpiece that is also strangely prison-like.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

Structure built from the skulls of vanquished foes.

A church of bones, decorated with 40,000 human skeletons.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

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

An eerie, derelict amusement park in Berlin.

Come stay at a live-in art installation.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Fall down the rabbit hole into a surreal journey of human consciousness "from ass to soul."

This classic restaurant features a gorgeous mirror-clad room.

A slice of central Asia in the middle of Berlin.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

This ghost town in Belgium will lose its street art when it ceases to exist.

A curious collection dedicated to human and animal anatomy and pathology.

The world's only museum devoted to the wonders of fluorescence.

Cat art as far as the eye can see.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

An ambiguous ambience emanates from this centuries old leprosy quarantine.