This abandoned, turn-of-the-century astronomy hub is now the subject of more photographs than it ever took.

Geological storytelling.

Containing a personal collection of more than 1,200 jugs from around the world.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

This ancient rock painting is the oldest evidence of humans’ love affair with honey.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

This mountaintop observatory is home to one of the world's largest reflective telescopes.

A completely underwater art museum sends a stark message about humans' impact on the environment.

A Franco-era dam flooded (almost) everyone out of this centuries-old Aragonese town.

The effect of this ancient form of image projection situated atop an 11th century Moorish palace is thrilling.

One of the world's oldest universities houses an incredible collection of anatomical models, mummified body parts, and human bones.

This house's itty bitty size means no humans allowed.

An architect transformed this abandoned cement factory into his castle-like workshop.

A celebration of solstice followed by a fiery purging of evils.

A rare set of strings by famed instrument maker Antonio Stradivarius is on display in the Royal Palace.

The lengthy skeleton of one of the tallest Spaniards of all time is on display in Madrid.

Science fiction's grandfather has a fittingly marvelous tomb.

Experience architect Le Corbusier's modernist design for living in the home he designed for himself.

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

Ghosts of France's colonial past.

Ancient paintings known as the "Sistine Chapel of Cave Art."

The Cimetière des Chiens et Autres Animaux Domestiques is one of the oldest pet cemeteries in the world.

The famous winding walk at Chartres is surrounded in mystery and myth.

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