A massive sculpture of an obscure Celtic coin that has become a symbol in Slovakia.

Different sections of the Zemun Fortress were built in the 14th and 15th century as a response to the advance of the Ottoman Empire.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

This 2,000-year-old Doric bridge is still open to pedestrian traffic to this day.

300-year-old villagers houses and traditional churches preserve a nearly lost piece of Russian history.

Former headquarters of the KGB.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

This snug medieval lane is one of the narrowest streets in the world.

On the cliffs of São Jorge in the Azores stand the remains of a lighthouse that was struck by a series of earthquakes.

A stunning architectural yet functional feat, towering over Oslo.

The rusted hull of a WWII German destroyer pokes above the surface in a Norwegian fjord.

The burning of this 12th-century church kicked off a campaign of Norwegian Black Metal terror.

In the hometown of the Catholic saint and Nobel Peace Prize winner, a memorial dedicated to her legacy.

A world-class theater sits hidden in this remote town in West Iceland.

Walk in the footsteps of the gods and straddle two tectonic plates.

The Adriatic's most famous wind can be reliably experienced in the city's Marina.

A galley-shaped memorial to the prisoners of an infamous fortress.

This Roman monument is surrounded by more recent construction, offering a stark contrast between ancient architecture and the modern urban landscape.

One of the tallest bell towers in Italy plays a particular melody at just two times each day.

One of the tallest lighthouses in the world also serves as a monument to the fallen of World War I.

Once home to one of the oldest banks in the world, this building is also where Marco Polo's famous travelogue was written.

The city of Parma's cathedral is home to one of the greatest illusionistic frescoes of the Renaissance.

This amazing medieval fortress stands atop a promontory along the famous Cinque Terre.

A medieval wash house where people washed clothes in a river allegedly formed by the tears of a mourning nymph.