Advice-columnist's bell tower, paid for with pennies.

A former major munitions plant that has been converted into a sprawling art space.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

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

This tiny chapel withstood a massive mudslide and flash flood.

The bomb-ravaged remains of of a colossal Neptune.

Five candy-colored villages on the Italian Riviera.

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

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

Two stone columns flank the grand Venice square, but there were supposed to be three.

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

The video game-themed street art first popped up in the French city.

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

The narrowest street in Paris.

Notorious artist squat renovated into legal studios.

Paris' linguistic guide to the international language of, yes, love.

A modern-day Lascaux cave underneath Paris.

This colorful statue welcomes visitors to a Barcelona park.

This semi-secret storybook hedge maze is also the oldest garden in the city.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

The world's oldest bookshop still in operation.