The commemorative stone column conceals a secret laboratory.

The fences outside some of South London's estates are made from recycled World War II stretchers.

The Tudor-style cottage in the middle of the square is not quite what it seems.

An architectural oddity hides in plain sight on this iconic London bridge.

Originally built for London’s cab drivers, this bright green hut now serves anyone a hot drink or meal.

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

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

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

The cedar tree in Highgate Cemetery earned its title by accident.

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

Dictionary Johnson’s favorite feline.

Giant, friendly pelicans in Central London, the most unlikely of places.

The London pub overlooks where the Mayflower was moored before setting sail for the New World.

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

After nearly 60 years, there's still a bear at Paddington Station looking for help.

London's smallest police station is barely the size of a phone booth.

An incarceration museum on the spot of possibly the oldest prison in England.

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

These medicine cabinet staples are part of the museum's collection of everyday objects.

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

Where America’s first doomsday cult awaited the end of the world.

This fountain was designed to honor the man who helped bring water to Barcelona.

An early 20th-century bullring converted into a modern shopping center.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.