Originally a small 9th-century fortress that had fallen into disrepair, Granada's famed Moorish palace and UNESCO World Heritage Site, the Alhambra, was reconstructed to become a royal palace and a "paradise on Earth" by the Moorish caliphs who ruled here in the 13th century. A century later, now in Spanish hands, it became Ferdinand and Isabella's Royal Court; even later, a Renaissance palace was built on the site. You'll have an opportunity to view it on a guided walking tour of Granada.