An ancient and majestic fortress that played an integral role in Portugal's road to independence.

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

A submerged village appears when dam levels drop.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

Houses are tucked between, on, and underneath giant boulders.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

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

A once-secret library of Freemason history in Catalonia.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

A temple to modernity, tucked away amid Barcelona's more well known museums.

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.

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

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

Mountain where Jesus was first tempted by the Devil.

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

This cemetery features modernist statues as strange as its name.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Spain's stunning solar energy plant.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

Junkbots and mud babies are the masterpieces in this fantastically sci-fi art museum.