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

The sign at the garden gate reads: "These Plants Can Kill."

A church that bred legends, and served as an inspiration for the Da Vinci Code.

Huge winged monument in the United Kingdom.

There are hundreds of secret WWII bases hidden in British forests. Built to fight a Nazi invasion, they remained unknown for decades.

In an isolated field near a dilapidated barn stands this chilling portrayal of the plight of the Nuba peoples of Sudan.

Detailed sandstone carvings show an array of symbolism and adorable animals.

This tangled English forest looks like something right out of a fairytale.

A unique journey back in time to an early 20th-century fairground.

A haunted slate mine turned concert hall and a hidden fairy garden.

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

The ruined abbey includes a rare surviving example of a monastic latrine.

A subterranean playground in an abandoned slate mine.

These haunting ruins belong to an ancient village that once had one hell of a view.

A little-known castle set in a nature reserve.

This water-powered cliffside railway is one of the steepest funiculars in the world.

This 19th-century island fort built to protect against an invasion by sea.

A spiral staircase connects the limestone cave with Pembroke Castle, birthplace of King Henry VII.

This series of Scottish caves has no clear purpose other than baffling historians.

A site of pagan worship which still attracts people looking for fairies.

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