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

This statue of one of the engineers who created the London Underground hides a ventilation shaft for the tube lines that run under the street.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

The commemorative stone column conceals a secret laboratory.

A memorial for public executions that dates back to the 14th century.

A mysterious suspended hand greets unsuspecting visitors at the Tower of London.

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

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

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

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

Only a few pieces remain of the structure that carried people and goods across the Thames for some 600 years.

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

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

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

This demon atop the Notre-Dame de Paris looks utterly bored.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

A public urinal so pretty, it was declared a national monument.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

A unique work of automotive art calls this shopping center home.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

A beautifully rebuilt windmill from the 17th century, situated along the Amstel River.

Each time a baby is born in Ghent, these streetlights flash in silent celebration.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.