Built by the patron saint of illusionists this Elizabethan manor house is riddled with secret cubbies for hiding priests.

Modern megaliths form this work of cosmic, Celtic landscape art.

These morbid carvings remind churchgoers of the inevitability of death.

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

The curious and tiny collection contains some very odd objects.

A mysterious bridge over a sunken Roman road.

A spooky juxtaposition of caves and graves gives this legend-filled cemetery a particularly haunting vibe.

19th century tunnels burrowed under Liverpool.

Hidden on the urban banks of a Manchester river are a series of abandoned waterside industrial sites.

The biggest and deepest Cold War bunker open to the public can be found in southeast England.

These legendary stone steps were once used to haul coffins up the rockface.

This amazing 15th-century mural remained hidden in plain sight for centuries.

Where Aleister Crowley attempted to seize the Hermetic Order of the Golden Dawn in a mask and a kilt.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

The highest peak in all of England is plagued by dangerously fickle climate shifts.

The U.K.'s first underground railway line is now a lively thoroughfare for runners and cyclists.

These medieval tunnels provided water to the city above through centuries of civil war and plague.

A group of glacial erratic boulders are improbably balanced on white limestone pedestals.

The abandoned transportation hub hides within the Glasgow attraction it once served.

This tunnel entrance is built to resemble a grand castle but no one is quite sure why.

It's possible to walk inside one of the largest Neolithic tombs in Britain.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

A sea cave with a waterfall and Viking past

A 600-year-old mini shrine guarded by a sword-wielding knight hides in a crumbling cliff face.