Semi-precious Blue John stones have been mined in this cavern system for centuries.

An enigmatic natural rock formation with a manmade passage cut through the center.

Perhaps the only prehistoric monument with its very own public bus stop.

A slightly surreal menagerie of structures that were lovingly spared from demolition and reconstructed in a field.

Asthmatic Charles Hyett's son built a fantastical garden for his father to convalesce in, alas it was too late.

This unchanged Victorian park is rumored to have been the inspiration behind Peter Pan's Neverland.

This unique tower has been home to malaria-fighting bats for 100 years.

Thousands of Mexican Free-Tailed Bats soar around an abandoned storm drain at sunset each summer.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

These flying foxes dangle from the trees around the library like fuzzy black fruit.

Each summer, the migratory bats living beneath the bypass form "batnadoes" at dusk.

A Roman spa buried deep beneath the City of London.

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

The storied English village that pretended to be insane inspired NYC's nickname and the fictional namesake in the DC Comics universe.

An engineering error ensured this cavernous 350-foot-long subterranean thoroughfare was never used as intended.

A Neolithic burial site built 1,000 years before Stonehenge.

A sturdy relic of Britain's once crucial gunpowder industry is now a haunting Cornish ruin.

6000-year-old site covered in more than 50 megaliths.

The tragic reality of a town riddled with rumors of haunts, chemical spills, and serial killers.

An abandoned castle owned and ignored by Masons carries a cursed history.

This dark, quiet forest on the outskirts of San Diego is dense with rumor and lore.

This charmingly homemade amusement park has been growing for 40 years.

European castle ruins in an American state park are actually the product of death and grief.