A bronze bust commemorates the heroism of the secret agents who led covert operations against the Nazis.

The plunge pool is a surviving relic of a rowdy royal residence.

These docile dragons are ideal inhabitants for the conservatory greenhouses.

Buried for centuries, this hidden cellar is all that remains of London's medieval Whitefriars Monastery.

This beautiful deer park was built so King Charles I and his court could go hunting while escaping a deadly plague outbreak.

An archive of ceramic eggs painted to record clowns' personal makeup designs.

A tiny replica of the iconic London landmark hides on the side of the steel structure.

The ritual has been performed uninterrupted for nearly 700 years.

Murals of the wild parties once held on the frozen River Thames.

Drink your espresso at a Victorian-era urinal in this underground-restroom-turned-coffee-bar.

One of the greatest movie directors of all time lived and worked in this London flat from 1926 to 1939.

A roadside shrine to a late rock god only remains thanks to the unyielding efforts of his fans.

More than a million titles fill the labyrinthine shelves of this prestigious private library.

This unique bridge curls up like a caterpillar to let boats pass and then unfurls again to span a small canal.

Black cat statues guard this temple-like Egyptian revival factory.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

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

A relic of Victorian grandeur hides beneath a busy South London road.

This overlooked street light once served as a KGB dead letter box.

The remains of the great moral philosopher reside in a university in London.

An eccentric 18th century naval officer built a ship's quarterdeck on his roof, the inspiration for Mary Poppins's "Admiral Boom."

Installed at a chaotic intersection, this gave London traffic cops a place to hang their heavy woolen coats.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.