The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

In 1943 the British military took control of this village, telling residents they had to leave temporarily. The villagers were never allowed to return.

Ancient Egyptian wigs, South American feather headdresses, a bounty of anthropological artifacts in Oxford.

This former abandoned hospital, a complex of stunning 19th century buildings, once housed 2,000 psychiatric patients.

This logic-defying 16th-century Tudor manor still stands to the delight and astonishment of onlookers.

Near Birmingham, England three and a half miles of top-secret tunnels housed a World War II “shadow factory” and a Cold War nuclear bunker.

Geodesic dome luxury retreat in the Scottish Highlands.

This antique prison is a tourist attraction with a sordid past.

Colin Stokes "got a bit carried away" and built a castle that looks like something out of Tolkien.

A curious collection of mechanical moving figures.

The ruins of an 11th-century Norman castle with a rare, perfectly circular shape.

A house of bones — but nobody is quite sure to whom they belong.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

This crumbling folly looks like an enchanted left over from Middle Earth.

Three bridges straddle a stream, one stacked upon the other.

This observatory within Europe's first dark sky park offers stunning views of the night sky.

Besieged by war, this castle ruin has crumbled into a peaceful picnic spot.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

A 200-year-old prison that now houses a peculiar crime museum.

This abandoned asylum in Wales might look haunted, but it's still beautiful.

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

A subterranean playground in an abandoned slate mine.

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

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.