London's largest outsider art museum.

A hermit's tiny cell built into the cliffside that saved him in South Pembrokeshire.

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

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

The oldest inn in England served brew to the crusaders.

A mysterious monument where a woman who records say never existed was burnt alive for being a witch.

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

A miniature Italianate fantasy village on the coast of Wales and the set of ITC classic "The Prisoner."

Below a historic English market town lies a secret underground city complete with kitchens, laundries, storerooms, and an underground lake.

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

This cramped crevasse saw the entire population of its island suffocated inside its depths.

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

Fascinating town where normal life interfaces with the occult.

A network of concealed passageways lies within a busy London Underground station.

At high tide this strange footbridge appears to have no purpose whatsoever.

The largest cave chamber in Britain—big enough to fit a whole cathedral inside.

The decaying ruins of Wales' first asylum for the mentally ill.

Museum about life, death, and cannibalism in the Stone Age.

A rocky sea serpent hides caves, blowholes, and a spectacular natural bridge.

A subterranean playground in an abandoned slate mine.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

The true age of this ancient stone circle is unknown, but its stunning vista isn't in question.

The highest peak in the United Kingdom has a history of physics, specters, and a pilgrimage of strange objects.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.