This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

This "floating railway" is one of the world's oldest monorail systems.

The architect of this fanciful complex called it an "oasis for humanity and nature in a sea of rational houses."

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

A 16th-century Andalusian palace.

This hauntingly beautiful cemetery outside a medieval citadel is full of winding paths and ivy-covered graves.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

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

Something's watching you.

This fairy-tale castle would make Dracula (who is said to have been imprisoned there) jealous.

A countryside Romanian cemetery filled with colorful crosses bearing lyrical, ironic, or satirical rhymes.

This massive underground salt mine now holds a sci-fi theme park in its depths.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

A sharp sculpture made of thousands of pieces of jagged glass.

Where commuters walk through remnants of an ancient Greek necropolis.

A museum marks and documents the site of the Titanic's launch.

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.

Apartment complexes built into huge repurposed natural gas tanks.

Collection dedicated to funeral rites, equipment, and mourning rituals of the Viennese.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.