Detailed sandstone carvings show an array of symbolism and adorable animals.

A modest stone circle in North Wales.

Ten 25-foot-tall, beehive-shaped kilns, abandoned in Death Valley.

One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

A sulfuric hellscape in southern Italy.

Virgil's many-mouthed gateway to the underworld.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

This tangled English forest looks like something right out of a fairytale.

The largest greenhouse in the world is home to over one million types of plants.

An abandoned horticulture institute gloomily presides over rows of derelict and vine-wrought greenhouses.

400-year-old garden, restored to beauty.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

The haunting concrete remains of a Nazi pebble crusher can still be found in this small French commune.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

A Turkish ghost town abandoned in a population exchange with Greece.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

A marvel of technology a century ago, this disused power station now offers a lovely glimpse into the industrial design of the past.

Ruins of a German Castle on top of a towering stone pillar.

A battle between nature and architecture in the Cambodian jungle.

The blood-soaked ruins of the castle where the murderous Blood Countess was walled in alive.

Haunted tuberculosis hospital built by the patients.

An abused and forgotten metropolis, abandoned for centuries.