This Gothic castle-like portal is a testament to the amazing craftsmanship of the navvies who built the railway tunnel.

This enormous spiral sculpture looks strangely out of place on the edge of a housing development.

Probably the smallest museum in the world, housed in a disused phone booth.

The wreck of a B-29 Superfortress now stands as a memorial left in the moors.

A headstone notes where the most famous of Robin Hood's legendary Merry Men is reportedly buried.

This old Victorian bathhouse is fed by an ancient spring.

A collection of throne-inspired sculptures dot the landscape of Wincobank.

As part of a larger public art project, three pillars honor the past of Wincobank.

A stretch of land where the sour-sweet vegetable is cloaked in darkness and grows so fast you can hear it crack, squeak, and pop.

Though much of the castle was robbed of its stones, the underlying earthworks are among the best-preserved in England.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

France's most famous cemetery, with some of its most curious tombs.

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

World's first "penitentiary," meant to be humane, drove men insane.

Semi-precious Blue John stones have been mined in this cavern system for centuries.

Artists have long been drawn to these atmospheric 12th-century ruins.

These medieval monastery ruins are surprisingly overlooked by most tourists.

A swath of France so devastated by war it is still forbidden to go there.