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

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

This mysterious underground cave in Shropshire dates back to the 18th or 19th century.

Home to the most complete dodo remains known - one head, and one foot.

The library houses an incredible collection of some of the world's most impressive books and manuscripts.

Ancient Egyptian wigs, South American feather headdresses, a bounty of anthropological artifacts in Oxford.

William Blake claimed to have painted this gothic masterpiece after encountering this nightmarish being in a vision.

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

These morbid carvings remind churchgoers of the inevitability of death.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

An 18th century monument regularly tagged with unsettling graffiti referencing a 1940s unsolved murder.

This small collection of rare books was uniquely locked up for safe keeping.

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

A village on the east coast of England that has almost completely eroded into the North Sea.

This tiny little pool is said to be home to a malicious mermaid named Jenny Greenteeth.

Puzzles within puzzles hide a golden treasure in this hedge maze.

On this wooded path, a stained-glass window creates a spellbinding forest cathedral.

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

One of Europe's oldest libraries.

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.

Although it appears ancient and mysterious, the quirky folly was actually built 200 years ago by an eccentric estate owner.

Fantastically decorated underground chambers built in the 1760s.

No one knows who created the statues or if they are arranged properly—let alone the artwork's real name.

Eyam took steps to quarantine themselves and keep the plague from spreading.