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

The abandoned funicular tunnel was a secret base for the BBC during World War II.

Rare collection of medieval books under lock and key.

Where condemned pirates met their grisly end at the gallows on the River Thames.

One of the oldest trees in Britain may have been witness to some of the country's formative moments.

This strange moor has a song written about it, Bronze Age carvings, and an alien sighting.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

This shell of a historic manor house on the Isle of Wight is said to be the most haunted site on the island.

A mysterious bridge over a sunken Roman road.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

Hidden on the urban banks of a Manchester river are a series of abandoned waterside industrial sites.

This former abandoned hospital, a complex of stunning 19th century buildings, once housed 2,000 psychiatric patients.

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

An intriguing three-sided folly is a testament to one man's devotion to Catholicism and the number three.

Museum dedicated to the UK's first charity for abandoned children, with keepsakes of the mothers who left them behind.

Black cat statues guard this temple-like Egyptian revival factory.

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

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

In 1943 the British military took control of this village, telling residents they had to leave temporarily. The villagers were never allowed to return.

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.

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

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.