Cliffside houses provide a spectacular view from their perch above the valley.

Incredible labyrinth of man made caves.

This historical Netherlands fortress still bears the marks of its single siege.

There has been an astronomical clock on this spot since the 14th century.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

A moving memorial to the fallen and missing from WWI trenches.

Two towns are linked by an engineering marvel masquerading as a boring suspension bridge.

Giant topiary dog once played a role in a terrorist bomb plot.

Of course Salvador Dalí lived in a castle...

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

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

This cemetery features modernist statues as strange as its name.

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

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

France's most famous cemetery, with some of its most curious tombs.

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

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.

This Parisian fountain is a little bit fantasy and a little bit nightclub.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

A 400-year-old church covered floor to ceiling in ex-voto offerings from the faithful.