The Alhambra is the only Muslim palace to have survived from the Middle Ages. Built by a bloody and threatened dynasty of Muslim Spain, it was preserved as a monument to the triumph of Christianity. Every day tourists in their thousands are entranced by its superb site, its towers and courts, its fountained gardens, its honeycombed ceilings and its intricate tile work. Much of what they see is the invention of later generations. Its highly sophisticated decoration is not just random but full of hidden meaning. Its most magnificent buildings were designed not by architects, but by philosophers and poets. It is a place of many mysteries. Even its purpose is not always clear. The Alhambra, which resembles a fairy tale palace, was constructed by slave labour in an era of economic decline, plague and political violence. Its beautifully decorated halls witnessed many murders. The Alhambra's influence on art, and on literature, Orientalist painting and Granada cinemas, Washington Irving and Borges, has been significant. Robert Irwin helps us to understand that story fully.