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

A unique seaside cave where Aleister Crowley faked his own death.

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

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

At night, bats patrol this magnificent 18th-century space in search of book-eating pests.

The world's oldest bookshop still in operation.

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

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The best place in the world to buy tinned fish.

An abandoned mine now resembles a post-apocalyptic landscape of derelict buildings and blood-red pools of water.

The final resting place of the great navigator, or maybe his brother.

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

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

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

This 19th-century fountain's namesake animal isn't what you think it is.

Giant topiary dog once played a role in a terrorist bomb plot.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

Pagan monument converted to Christianity with the population.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

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

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

A towering monument in Spain has proven to be more labor-intensive than initially planned.

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

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