France's most famous cemetery, with some of its most curious tombs.

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

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

The final resting place to 300 Victorian-era pets hides inside the city park.

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

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

An unusual round church in London with a Templar past.

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

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Copenhagen's celebrated theme park and gardens.

The world's biggest floating museum in Gothenburg, Sweden.

Sweden's oldest animated sign is still lighting up the skyline today.

Now a hotel, this former bank was the site of a robbery that spawned a psychological phenomenon.

A man has revenged his true love's betrayal through tears and stone genitalia.

Sweden's "good old days" painstakingly re-created in a model village.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This chimerical bridge/tunnel appears to dead end right into the sea.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.

Elaborate tile work in this railway station tells the story of Portugal.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.