These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

Art Deco and “Wrenaissance” mash-up, this recently restored royal residence has been home to kings and comes with secret monkey passages included.

These lovely Turkish-styled baths were brought back to life after winning a reality show competition.

A century-old tradition has culminated in a small but singular collection of feline effigies.

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

These stark white cliffs were spat up by the sea and are slowly being retaken by it.

Pop culture has helped to keep this iconic British building from being destroyed.

Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

A hidden treasure in London with a rich medieval history, and the resting place of many luminaries.

A modern English garden of eccentric beasts, follies, and oddities.

Surreal riveted sea forts once protected the Kent shores from German attack.

This 19th-century island fort built to protect against an invasion by sea.

This 500-year-old Tudor home is a treasure trove of history and mystery.

The remains of a small medieval chapel mark the legendary birthplace of the patron saint of Wales.

The artist David Nash planted a circle of trees in 1977.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.

A hermit's tiny cell built into the cliffside that saved him in South Pembrokeshire.

The barrel-made lookout from Shackleton's final ship is tucked away in the crypt of one of London's oldest churches.

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

This century-old grotesque has a mysterious history and may not actually be a rabbit.

This single-track road rewards brave drivers with stunning Scottish scenery.

This macabre monument atop an ancient well gives a nod to a brutal episode in Scottish clan history.

The Stonehenge of Wales is one of the grandest neolithic dolmens still in existence.

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