In downtown Oslo, a menacing and terrifying relief clings to a church wall.

This floating sculpture of ice is a poignant reminder of nature's power.

This handsomely carved wooden church is more than 800 years old.

A stunning architectural yet functional feat, towering over Oslo.

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

Engineering ingenuity during the battle of Gibraltar.

Many of the tombs contain victims of yellow fever epidemics.

A beautiful little castle with a rich history now home to the Archives of the Spanish Air Force.

This modernist bridge highlights the bear as a symbol of Madrid.

After the queen of Spain had a dream where these statues fell and crushed her, they were removed from the palace and given new homes around Madrid.

The world's most elegant power lines.

These ancient artifacts are a testament to the enduring significance of the bull in Spanish culture.

A haven for book enthusiasts across the street from Retiro Park.

Inaugurated three times, this tower offers some of the best views of Madrid.

This enigmatic artifact is a rare depiction of an ancient Iberian noblewoman.

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

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

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

A New York–based physician returned home to Spain to build his own elaborate monument to Christopher Columbus.

The ruins of an ancient stadium that hosted gripping chariot and horse races.

The Roman city was the birthplace of various emperors and is home to one of the empire's most impressive architectural feats.

An iconic and controversial ancient Iberian funerary urn with a hauntingly penetrating gaze.

The current seat of the Parliament of Andalusia was once the epicenter of the Great Plague of Seville.

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