Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

The atmospheric ruins of a historic church can be found on a hill above the city of Oviedo.

A small house in Tazones, completely covered in shells.

Stormy conditions send jets of seawater bursting through holes in the cliffs.

A living art gallery painted on a canvas of Monterey pine trees.

An archeological treasure trove stumbled upon by a couple of children.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

This huge abandoned fortress hidden inside a mountain holds a world of subterranean secrets.

This tiny river island switches sovereignty every six months as part of a rare, centuries-old agreement.

The eclectic observatory castle of a 19th-century astronomer and explorer.

Winston Churchill painted this lake during his stay Woolsack Castle in the Landes forest.

Lady Liberty's original designer installed a little clone in this French fountain.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

The largest underground church in Europe.

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

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

The experimental test tracks of a retro-futuristic monorail still stand in the French countryside.

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

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

Science fiction's grandfather has a fittingly marvelous tomb.

A centuries-old complex of hand-dug stone chambers has sheltered locals in times of trouble.

This small commune with an even smaller name appears to have an unlikely amount of dead ancestors.

Ghosts of France's colonial past.