Château de Chambord, France

Dawn light on Chambord's main facade, seen down the long approach, with its roof bristling with lantern towers, chimneys and dormers like a small city built on top of a palace. That crowded skyline is the reason it belongs here. Francis I began it in 1519 as a royal hunting lodge, though he spent only a few weeks there in total, and work carried on long after him. It is the largest château in the Loire Valley, with nearly 300 fireplaces. At its heart sits a double-helix staircase, two spirals that wind past each other without meeting, often linked to Leonardo da Vinci, who died that same year. Climb it to the roof terraces and you can walk among the towers you see in this photo.