This abandoned gold mine found a second life as a post-apocalyptic film set.

Sanctuary on a ridge near an ancient shrine to a "Black Madonna" built by the founder of Opus Dei.

The highest peak in mainland Spain is said to be the final resting place of a Muslim king.

A curious memento mori hangs in the magnificent Cathedral of Segovia.

Marvel at this massive waterspout fueled by the incoming tide.

Long tunnels run under the ancient chariot racing circuit to the tower.

Rumors and legends of secret Nazi activities surround this eerily remote island mansion.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

Moorish signal station on a stratgic rocky outcrop.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

Gods clash with machines in a power plant regenerated as a museum.

Rome's ancient Etruscan rival, now a park full of ruins.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

Rome's semi-secret peephole vista is also a former Crusader stronghold.