The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

An unusual round church in London with a Templar past.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

An eccentric aristocrat brought these Australian natives to their current Scottish home.

Even after the church tried to wipe the practice out, this pagan festival lives on each year in a small Scottish village.

This Scottish manor house is a lush relic from the life of a literary great.

This huge concrete map of Scotland was built as a thank you gift from a Polish soldier.

This tiny island featuring 9th-century Viking ruins is only accessible at low tide.

Britain's only herd of free-ranging reindeer.

Long abandoned underground complex to keep royals safe from a nuclear war that never came.

One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

A mysterious monument where a woman who records say never existed was burnt alive for being a witch.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

The final resting place to 300 Victorian-era pets hides inside the city park.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

Remnants of a Victorian garden feature sitting in public woodland.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

The secret room where early Bolsheviks cranked out propaganda fliers on a smuggled printing press.

The decaying remains of a once-luxurious Soviet spa town.