Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.

A beautiful and classically designed villa, with an hourly infestation of monsters.

This tiny hotel perched atop a 50-foot tower really puts things into perspective.

An aluminum skeleton brings Chinese mythology to the French shore.

The sunken structure looks like the victim of a catastrophic flood.

This small island, a byproduct of 19th-century canal construction, is now home to a charming Japanese garden.

A massively oversized measuring tape sculpture sits inside a hidden yard.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

A medieval house adorned with enigmatic carvings, including one of a man displaying his masculine attributes.

A self-built mosaic house and sculpture park.

A magnificent, long-abandoned castle built in the wake of the reconquest of Spain.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A fortress on this island housed the mysterious prisoner known as the "Man in the Iron Mask" for more than a decade.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

Thousands of flamingos and other bird species flourish in these Camargue wetlands.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

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

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

The world's largest model of our planetary system.