"In the Dark" Restaurant in Paris offers dinner in complete darkness.

This museum houses an imposing skeleton army comprised of creatures great and small.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

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

This Parisian gem is one of the most incredible ethnographic museums in the world.

A modern-day Lascaux cave underneath Paris.

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

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

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

Notorious artist squat renovated into legal studios.

Visitors are treated to a stained glass kaleidoscope interior inside this work of art.

Bored potato-guarding Nazis etched their thoughts onto a brick storage building in Copenhagen's Meatpacking District.

The gilded, masterful astronomical clock will calculate time, dates, and planetary positions for thousands of years to come.

Climb to the top of its spiral spire for spectacular views of Copenhagen.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

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

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

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

This frog-themed restaurant was frequented by Picasso, Saint-Exupéry, and more.

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

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

The oldest stone house in Paris was built by its most famous alchemist.

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