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

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

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

This influential Renaissance-era library was once the haunt of kings and monks.

A hidden medieval crypt where a famous legend says the devil used to teach black magic.

An unusual but excellent display created in the 1930s as propaganda against the Freemasons.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

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

This surreal-looking tree pruned more than 1,000 years ago is still producing olives for oil.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

See replicas of Europe's most famous cave paintings and even some of the animals that feature in the art.

An abandoned Indian-inspired mansion.

The extensive relics of an ancient Roman and Phoenician fish processing plant hide in a town park.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

Numerous sculptures set along hiking trails symbolize and idealize the relationship between man and nature.

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

Mysterious Spanish catacombs of unknown origins.

A Spanish town built into the cliffs.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

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