A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

Plenty of old carney magic still haunts this photogenic amusement park.

An English explorer's vast natural history collection has the first realistic dioramas of animals staged in their natural habitats.

A vast archive of cultural artifacts collected from numerous expeditions across Africa and Asia.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

An abused and forgotten metropolis, abandoned for centuries.

The remains of a grand castle that may have inspired Bram Stoker's Dracula.

A ruined hotel with an unlucky history and an eerie present.

Super-heavy Nazi architectural experiment.

Home to 10,000 medical specimens including the remains of Rudolf Virchow's extensive collection of pathological specimens.

Right up until the 20th century this network of man-made caves was the biggest village in Eastern Armenia.

This abandoned villa of makeshift buildings was once the home of dancer Elis Sinistö.

The only residents of this abandoned housing development full of identical castles are stray cats and dogs.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

Underground monastery and fortress.

The decaying remains of a once-luxurious Soviet spa town.

Fortifications built for a Soviet invasion that never came now sit abandoned in a losing battle against nature.

George Martin's Caribbean recording studio now rots within the shadow of an active volcano.

A merchant court dedicated to the fictitious King Arthur is heavily adorned with bizarre Renaissance art.

The vibrant buildings in the “capital of the comic strip” celebrate the art form that made it famous.

This remote mountain shrine is one of the most sacred Zoroastrian temples remaining in the world.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.