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

Large-scale contemporary artworks tower over fields and lurk in forests around a Jacobean manor house.

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

The stately remains of Llywelyn the Great's mighty fortress.

The cedar tree in Highgate Cemetery earned its title by accident.

This foolish Victorian sea fort was converted to a deluxe hotel.

A pub that is literally in the middle of nowhere, but continues to do business.

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.

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

The oldest inn in England served brew to the crusaders.

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

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

Largest lake in Great Britain measured by surface area.

England's most notorious suicide spot.

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

Western Europe's only representation of a Roman goddess still in its original location sits in an unassuming park.

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

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

This stately estate house features a tower covered in a bright, modern mural.

The monster at the center of the Darwin Center Spirit Collection.

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

England's oldest surviving hedge maze has been confusing visitors for over 300 years.

Remnants of cells from the most notorious London prison may lie in the basement of a rare Victorian Gin Palace.

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