Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

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

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

The morbid items in this small and hidden museum are not for the weak stomached.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

The best way to get a sneak peek at the movies.

Outstanding taxidermy dioramas showcase the grandeur of the continent's wildlife with spooky realism.

This hidden oasis features a stunning view of the Hudson River and the Palisades from a castle-like museum.

This castle-like building in Manhattan helped destigmatize cancer in the 19th century.

During the 19th century, you could pay for violence off a prix fixe menu on this Manhattan street.

Church in Manhattan holds the bloody sock of Padre Pio, among with many other unusual relics.

The 28-foot granite map plots the locations of 40 theaters in New York City.

The first piece of public art dedicated to LGBT rights.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

The most confusing clock in New York.

A little lighthouse in New York City, surrounded by mysterious stories of insanity-driven construction.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.