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

This coffee shop lies hidden beneath a historic church.

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

Hear the quietest sound from across the dome.

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

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

An abandoned 1970s theme park that has been turned into a space for waterfront walking.

One of the largest underground systems runs under Canada's largest urban center.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

This bird-loving brewery is situated in an old municipal bathhouse, nestled beside a 300-year-old windmill.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

An ancient octagonal weather station named for the eight Greek gods of wind.

The hallucinogenic center of the ancient world.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

Erosion and various mineral deposits give this striking canyon its distinct color and soft appearance.

This quiet park's strange sedimentary spires were named after Kodak's color film.

The rogue roots are gradually consuming some of the historic marble grave markers.

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

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

An impressive Sasquatch statue marks the spot of a fated Bigfoot encounter that changed a community.