A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

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

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

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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

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

A Gothic cathedral created from volcanic rocks.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Macabre astrological automaton clock dating to the late 1400s.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

Go inside to really appreciate this 500-year-old technological masterpiece.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

This ancient market is often referred to as the oldest shopping mall in the world.

This ancient trail climbs the mountain where a Latin League cult worshipped Jupiter, its main deity.

This large, circular tomb is the final resting place of the first emperor of Rome.