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

The secret wartime bunker built on the platforms of an abandoned Tube station.

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

The 2,000-year-old beam is tucked within the pedestrian entrance to the old London Bridge.

A portly statue of a golden boy commemorates an unusual cause of the Great Fire of London: the sin of gluttony.

There's an exclusive Beefeaters pub hidden in the Tower of London.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

This pump on the bad side of Victorian London betrayed a horrifying revelation about the water supply.

A museum wholly devoted to juvenescence.

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

This one has sailed five times as far as Sir Francis Drake's famous ship.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

A plaque hangs near the execution place of the Scottish Independence leader famously depicted in "Braveheart."

This luxury shopping lane has been protected by its own tiny police force for over a century.

Public access to clean drinking water was an instant hit among the masses.

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

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

A naturally mummified 2,000-year-old man.

A collection of comics, graphic novels, animation and caricatures devoted to exploring this often overlooked art form.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

Scattered throughout London are ancient remnants of the city's former bounding wall.

A historic London pub with prison cells in the cellar and a "spy room" on the second floor.

A collection dedicated to the treatment of disease, held in London's oldest hospital.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.