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

The first geometric self-supporting spiral stairs in Britain are a truly beautiful sight.

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

A clock designed to run with perfect accuracy for 10,000 years.

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

London's smallest police station is barely the size of a phone booth.

A little slice of Japan and its aesthetics in London's Holland Park.

Hidden beneath the streets of London is a secret subway that only carried mail.

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

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the Harry Potter films.

Flaming barrels of tar race through these village streets on Bonfire Night, a tradition that dates back centuries.