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

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

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

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

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

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

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

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

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.

Hear the quietest sound from across the dome.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Eighty million natural history specimens call this gargantuan museum home.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.