Britain’s longest ancient monument, this great 8th century earthwork was built to mark the boundary between what would become England and Wales.

The oldest working mechanical clock in the world.

Unusual British home built to disguise a water tower.

A headstone notes where the most famous of Robin Hood's legendary Merry Men is reportedly buried.

A medieval replica of King Arthur's legendary table, the Round Table hanging in Winchester Castle was decorated by Henry VIII.

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

Eighteenth-century home, where Herschel discovered the planet Uranus.

In the ruins of Glastonbury Abbey lies the alleged resting place of the legendary king.

This oak sculpture at the edge of a small woodland is nine feet tall and shrouded in mystery.

An extraordinary collection of scientific instruments - and Einstein's chalkboard - inside the world's oldest purpose built museum building.

The first archaeological site discovered by aerial photography.

This Cheshire museum has cuckoo clocks, a rare pipe organ and vintage motorbikes. But mostly cuckoo clocks.

A labyrinthine underworld of tunnels and caverns hides beneath the city.

Europe's largest prehistoric mound – burial site of a legendary king?

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

The Bristol Camera Obscura housed in an ancient windmill.

A wonderfully eclectic Victorian aquarium lies in the basement of the Horniman Museum.

Used as an example in one of the first dictionary entries for "museum" in 1706.

What happened to the three lighthouse keepers who vanished from this place remains a mystery over a century later.

This museum inside a museum tells the story of London's timepieces.

This giant wooden treehouse within a sprawling garden has its own eatery.

A historic cave in Scotland once served as a hiding place for a famous Covenanter.

The largest known medieval map of the world.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.