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

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

Mysterious Spanish catacombs of unknown origins.

Considered the birthplace of the Copper Age and Bronze Age, the river is tinted red from 5,000 years of mining.

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

Village situated on a narrow volcanic escarpment.

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

The morbid items in this small and hidden museum are not for the weak stomached.

This Funeral Hearse Museum represents the finest in cadaver transportation.

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

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

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

Wonderland replication in progress by one persistent man.

An enchanting monastery in the Spanish countryside appears lifted from a fantasy tale.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

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

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

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

A landscape decorated with enormous skull sculptures.

A Spanish forest is filled with mysterious stone carvings.

Commonly acknowledged as the only public monument to the Devil himself.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.