This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

This fountain is dedicated to the workers who perished constructing the Fréjus Rail Tunnel.

The intricate geometry inside this Baroque-style dome was designed to create "terror of the human soul."

An architectural oddity where the triglyphs of the courtyard of walls create an optical illusion.

A room filled with frescos that make it seem like the walls are crumbling down while giants die in despair.

It took more than 300 years to build this church, which is home to two sacred vessels believed to hold the blood of Christ.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

An exclusive waiting room built for the royal family in the 1920s is hidden in Milan’s central station.

A brutalist gem towering over the heart of Milan.

This church looks more like a spaceship than a house of worship.

Architect Le Corbusier built his friend a cubist house to match his impressive collection of cubist art.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

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.

Eighty million natural history specimens call this gargantuan museum home.

An early-19th-century hotel with a past that is steeped in the Civil War.

The first public building in Savannah to offer air conditioning was a luxurious cinema that still operates today.

A monument celebrating the idea of reaching inaccessible places.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

Thirteen pastel palaces in downtown Charleston add a gorgeous splash of color to the city.

A stack of stones steeped in Irish folklore, much like the hero they're connected to, hide in plain sight.

Once the most flame resistant building in the country, the South Carolina Historical Society building was almost burnt down in a fire.

Oldest unrestored plantation house in America that is open to the public.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.