A meandering boardwalk across the bogland leads to a "stairway to heaven" with sublime views.

China’s breathtaking futuristic library is lined floor to ceiling with fake books.

18th century anatomical amphitheater of the Royal College of Surgery of Barcelona.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

This massive library holds what was once the largest book collection in the world.

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

A modern-day Lascaux cave underneath Paris.

Monasteries on rock pillars, once accessible only by frayed ropes.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Built during the Scottish boom in the oil industry, the village was never inhabited.

A 16th-century horror show built in a lovely Italian garden.

A tomb with a window to ensure the interred wasn't buried alive.