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

A landscape decorated with enormous skull sculptures.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

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

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

A lush indoor jungle fills this bustling Madrid transportation hub.

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

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.

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

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

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

Wonderland replication in progress by one persistent man.

Week-long block party becomes a competition for the best decorated street.

Bacteria and algae give the salty water its bubblegum hue.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

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

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

Mountain where Jesus was first tempted by the Devil.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

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.

A beautiful but toxic fountain of mercury.