Castle of Zafra, Guadalajara province, Spain

Castle on a crag. Castle of Zafra, Guadalajara, Spain

Perched atop a sandstone outcrop high in the Sierra de Caldereros stands the Castle of Zafra. When the Christian kingdoms of northern Spain took the region from its Moorish defenders in the 12th century, they built this castle on the site of an older fortress to defend the borderland between the two powers. Over the years, it withstood countless battles of the Reconquista—the military campaigns waged by Christian kingdoms against Muslim rule in Spain—as well as in the Castilian Civil War of the 14th century.

When the fighting ended in the late 15th century, the Castle of Zafra was no longer strategically important and began to fall into ruin. In 1971, Don Antonio Sanz Polo, a descendant of the castle's last warden, bought the site from the Spanish state. He then spent the next 30 years restoring the castle. These days, you're more likely to see the Castle of Zafra on the screen than in a history book—it was used as a set for several episodes of the sixth season of 'Game of Thrones.'