A plaque marks the underground site of one of London's "lost rivers."

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

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

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

Huge winged monument in the United Kingdom.

Where Aleister Crowley attempted to seize the Hermetic Order of the Golden Dawn in a mask and a kilt.

A unique tribute to the millions of animals who served and died for the British military.

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

This network of narrow, medieval passages has the most delightful name.

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

Used as an example in one of the first dictionary entries for "museum" in 1706.

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

This historic abandoned train station looks like a stop for ghost trains.

The taxidermied remains of a once-great parrot.

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

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

One of England's most famous churches hides a pair of little known architectural treasures.

Museum dedicated to the UK's first charity for abandoned children, with keepsakes of the mothers who left them behind.

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

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

Shiny Brutalist box commemorates a pioneer of electricity and houses a railway transformer.

The biggest and deepest Cold War bunker open to the public can be found in southeast England.

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

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