The ritual has been performed uninterrupted for nearly 700 years.

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

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

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

An extraordinary library and archive dedicated to the history of the Arctic and Antarctic poles.

An ordinary lamppost situated in the middle of Cambridge has an unusual moniker and history.

Numberless clock creates a meal of time for the dreaded, insectile Chronophage.

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.

One of several Lilliputian portals that are ready to transport passengers to other dimensions, if they can find them.

This tree was grafted from the actual tree that led Isaac Newton to ponder the theory of gravity.

An unusual artwork dedicated to a unique man that entertained people visiting Cambridge while raising money for charity.

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

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

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

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

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

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

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

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

The commemorative stone column conceals a secret laboratory.

The lab where the scientist made his groundbreaking discoveries is preserved on the basement floor of the Faraday Museum.

The sculpture of the deceased cockatoo flops atop its personal plinth.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.