These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

The commemorative stone column conceals a secret laboratory.

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

The ritual has been performed uninterrupted for nearly 700 years.

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

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

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.

A Roman spa buried deep beneath the City of London.

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

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

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

Scattered throughout London are ancient remnants of the city's former bounding wall.

The remains of Crystal Palace Great Exhibition of 1851.

Hear the quietest sound from across the dome.

Eighty million natural history specimens call this gargantuan museum home.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

The world's oldest grape-producing vine has survived four centuries of turmoil and even has its own anthem.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

A Swedish phone box converted into an informal village library.

A tiny town hall—in Sweden's one-time capital—might be the smallest in Europe.

Sweden's oldest street has not changed for nearly a millennium.

This poignant sculpture of a gnarled weapon is a symbol of non-violence.