Victorian-era Londoners really wanted to believe this 17th-century cistern was actually an ancient artifact.

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

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

One of the few remaining examples of 19th-century London’s attempt to clean up its reputation.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

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

These ornate arches show how the course of the River Thames has changed.

A monolithic monument in Greater London.

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

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

Children's hospital in London that operates on royalties received from Peter Pan, which J.M. Barrie signed over in 1929.

The "lost friend” is the most famous of the six moai statues that were removed from Easter Island.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

A Roman spa buried deep beneath the City of London.

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

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

This elaborate Byzantine-style building was designed for a not-so-pretty purpose.

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

This home on a quiet suburban street is completely covered with vibrant mosaics.

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

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

The Metropolitan Police refurbished the blue box (perhaps not coincidentally) the same year "Doctor Who" returned to TV screens.

A special shop catering to the needs of things that go bump in the night, and also helps kids become writers.