Surreal riveted sea forts once protected the Kent shores from German attack.

An abandoned tank sits in an empty London lot as a symbolic middle finger to local city planners.

One of the earliest large-scale "hyper" roofs in the U.K. is now a derelict roadside attraction.

These ancient ruins were the final resting place of King Henry II's mistress.

A petite castle folly in the English countryside.

Under a church hides a forgotten 13th-century ossuary containing the remains of around 2,500 people.

A retirement home for soldiers that can trace its history to the Elizabethan era and beyond.

The longest and steepest staircase locks in the United Kingdom.

Every hour on the hour a naked heroine and her leering foil appear from this giant cuckoo clock.

All that remains of the medieval palace of the famous "Black Prince."

All that remains of the only English cathedral destroyed in the Protestant Reformation.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

The world's largest collection of witchcraft regalia.

The secret wartime bunker built on the platforms of an abandoned Tube station.

On this wooded path, a stained-glass window creates a spellbinding forest cathedral.

Scotland's only funicular railway is also the United Kingdom's highest.

A musical composition 1000 years in length plays at the Trinity Buoy Wharf in London.

Possibly the oldest of Britain's ancient henges is also one of its most stark.

A naturally mummified 2,000-year-old man.

An incarceration museum on the spot of possibly the oldest prison in England.

A historic house left in "dramatic still life."

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

The television series' iconic giant foot was borrowed from this classical painting.

One of the world's largest collections of pathological specimens.