Eighty million natural history specimens call this gargantuan museum home.

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

An unusual round church in London with a Templar past.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

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

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

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

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

The video game-themed street art first popped up in the French city.

A beautiful Victorian statue shows France's enduring love of the rhinoceros.

The tomb of history's greatest potato promoter is surrounded by tubers.

Stripes of human ashes cover a back lawn in the most sought-after burial grounds in Paris.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

A museum of magic with a Sadist past.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

The attic of a four-century-old canal house hides a clandestine church.

A beautifully eclectic mix of architectural styles.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

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

Founded in 670, this ancient mosque is an architectural time portal.