A small brick parlor house and artist's studio located in the wilderness is surrounded by imposing suburban palaces.

A double agent hid information for the Soviet Union beneath this bridge for more than 20 years.

This sturdy, circular stronghold served as one of the forts that protected the Venetian Lagoon.

According to tradition this is the oldest church in Venice, but its actual age is a mystery.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This deconsecrated church has seen many uses, from a tobacco storehouse to a cinema.

100 year tradition of fist fights, marked by marble footsteps.

The only museum with its curator—and her pets—buried inside.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

In the past, Renaissance sex workers were encouraged to entice customers on this bridge.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

Go inside to really appreciate this 500-year-old technological masterpiece.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

First founded in 1472, this is the oldest bank in the world. Its history may explain why we call financial institutions "banks."

Nine caves filled with recently-discovered archaeological finds under the houses and the streets of the most ancient district of an old town.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Caligula's colossal pleasure ships, discovered by Mussolini only to be lost in flames.

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

A restaurant and observation deck built in a unique broadcasting antenna.

The most visited, and possibly most controversial, museum in Germany.

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

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

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.