This 16th-century monastery has been turned into a surrealist architecture compound.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Resting on a hill overlooking the coast, these medieval ruins look completely deserted save for their restored chapel.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

This French "sea of rocks" is packed with stunning rock formations and its own medieval castle.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

If they push on just the right spot, even the weakest person can move this titanic boulder.

Green labyrinth formed by a karstic maze hidden in a preserved oak forest.

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

An architectural oddity of six stories, accessed by graceful ramps.

A chapel on a volcanic core, marking the end of a successful journey.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

The largest medical and anatomical collection in France lies hidden from the public.

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

Indents in the pavement are all that remain from a grisly death machine in Paris.

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

France's national museum of scientific and industrial instruments.

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

This Danish rock field is actually a sprawling ancient cemetery holding the bodies of 700 Vikings.

The world's largest maze is a nature park with nearly 200 decision points.