High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.

These lovely Turkish-styled baths were brought back to life after winning a reality show competition.

A hidden tunnel leads to an abandoned slate quarry that's now a secret swimming spot guarded by cliffs.

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

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

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

A strange rock with a sinister reputation lurks within the crimson waters of this Scottish glen.

This hidden green space is the city's second largest conservatory.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

There are plenty of wonderful panoramic vistas in Edinburgh, but not many are hidden smack in the middle of the Old Town.

This artist's home turned gallery/museum preserves the creator's love of "Eastern" influences.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

Accessible only at low tide, the deserted island is dotted with World War II ruins.

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

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

The mystery of this small, brick pond eluded its possibly only investigator until his death.

Ruined castle with subterranean vaulted Goblin Ha' or "Goblin Hall."

This beautiful "lagoon" is actually a toxic soup filled with cars, carcasses, and trash. When warnings couldn't stop people from going for a dip, the town dyed it black.

Charles Babbage's proto-computer, painstakingly brought to life.

The last inhabitants of one of the U.K.'s most remote islands were evacuated in 1930.

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

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