A monument to the three wars that led to German unification towers within a Berlin traffic circle.

Metro station with a claim to rock n' roll fame.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

2300-year-old Roman road connecting the empire.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

After it was swallowed by a Georgian mansion, this medieval castle remained forgotten for centuries.

The mummified heart of a saint lives on in this church—after a brief hiatus when it was stolen.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

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

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

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

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.