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

A gorge full of caverns where early humans lived alongside cave hyenas, giant mammoths and wooly rhinoceroses.

There's a labyrinth of medieval chambers hidden deep below a 15th-century pub.

This Scottish manor house is a lush relic from the life of a literary great.

A hidden tunnel leads to a medieval queen's shrine buried beneath a parking lot.

Britain's only herd of free-ranging reindeer.

Near Birmingham, England three and a half miles of top-secret tunnels housed a World War II “shadow factory” and a Cold War nuclear bunker.

This tiny little cave was said to have been a refuge for a saint with a glowing arm.

This tiny island featuring 9th-century Viking ruins is only accessible at low tide.

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

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

A midnight snack that lights up the night.

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

This picturesque archeological site looks like it was pulled straight from a fantasy novel.

A petite castle folly in the English countryside.

During this Shetland Islands celebration, hundreds of torch-carrying "guizers" lead a procession to burn a viking longboat.

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

This elaborate Byzantine-style building was designed for a not-so-pretty purpose.

Legend says this cave housed a 16th-century cannibal and his family of 48.

A statue in the heart of Edinburgh honors a bear that served in the Polish military during World War II.

A fernery hidden by neglect is uncovered, and an ancient specimen along with it.

Long abandoned underground complex to keep royals safe from a nuclear war that never came.

This lovely little burbling creek is actually a deadly waterway that has dragged down everyone who ever set foot in it.

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