An eerie collection of the surviving structures from a past celebration of the future.

Spain's largest bullring offers a unique glimpse at architecture and history.

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.

The world's largest wooden structure.

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.

Limestone grottoes turns everyday objects into stone.

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

A beautiful and classically designed villa, with an hourly infestation of monsters.

Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

This tile-work piece featuring a chicken riding in carriage is both a remarkable artistic creation and a social commentary of politics and culture in 17th-century Portugal.

This unique architectural wonder is also tied to one of the 20th-century's most renowned writers.

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

The world's oldest bookshop still in operation.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

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.

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

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