A panoramic view of the northwest façade of Château de Chambord. Built between 1519 and 1547 by King Francis I as a hunting lodge, it was heavily extended afterwards. The château is an example of Renaissance architecture, which blends traditional French medieval forms with classical Renaissance structures. This château is the largest of the Loire Valley, measuring 156 metres (512 ft) long and topping 56 metres (184 ft) in height. Chambord has been a UNESCO World Heritage Site since 1981.Photograph: Benh Lieu Song