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

Local legends say that fairies used to dance in the moonlight here and invite handsome young men into their grottoes.

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

An eccentric 18th century naval officer built a ship's quarterdeck on his roof, the inspiration for Mary Poppins's "Admiral Boom."

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

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

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

Human-made caves excavated to hide a secret society of wealthy pagans.

Art Deco and “Wrenaissance” mash-up, this recently restored royal residence has been home to kings and comes with secret monkey passages included.

Huge concrete structures designed as an early warning system for Britain to detect enemy aircraft.

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.

A village on the east coast of England that has almost completely eroded into the North Sea.

This hospital once pioneered the use of electroencephalograms, but fell into maltreatment, abuse, and eventual abandonment.

One of Europe's oldest libraries.

An English artist has turned an unassuming ex-council house into a time-lost house of mystery.

Follow the original medieval paths that wind through this intriguing section of the city.

This romantic, decaying 13th-century ruin on the edge of Sherwood Forest is reputedly one of England's most haunted places.

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

A friendly pub with a sordid past in cock fighting.

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

St. Mary's Asylum was isolated and abandoned before being converted into a Bed and Breakfast.

A open air theatre built on a cliff by an eccentric British woman.

This Gothic Revival castle used as a shooting location for "The Secret Garden" and other films.

Stonehenge has nothing on Castlerigg’s views.