Château de Chambord audio guide,
five stops, free.

You are on the far side of the water, and from here Chambord does something no other château on the Loire quite manages: it looks like a town someone has set down on a lawn. The walls are plain. Everything happens on the roof. Henry James wrote that the towers, cupolas, gables, lanterns and chimneys look more like the spires of a city than the salient points of a single building, and from this bank you can see exactly what he meant.

Start in the middle. The block with the two big round towers facing you is the keep, and for the first years of the building site it was the whole idea: a square palace with a tower at each corner, begun for Francis the First. On the sixth of September 1519 his chamberlain, Francis de Pontbriand, was ordered to begin. War in Italy interrupted the work, the money dwindled, the foundations in this marshy ground were difficult, and by 1524 the walls were barely above ground level. Then the king lost the battle of Pavia and spent two years a prisoner in Madrid. When he came back, around 1526, he changed the plan: two wings and a walled courtyard were added round the keep, and those are the long ranges running out to the corner towers on either side of you.

Now the question nobody can answer: who designed it. No plan and no text of the time names an architect, and the building-site records were scattered or destroyed at the end of the eighteenth century. What the estate will say is that the building shows the influence of Leonardo da Vinci, and that argument belongs to the staircase, the next stop.

Look at how the walls are drawn: horizontal mouldings between the floors, flat pilasters rising between the windows. That part is Italian. The round towers, the moat and the enclosure are the opposite, a deliberate memory of the fortified castle more than thirty years after artillery had made such castles useless. The estate reads them as allegory: the last chevalier king dressing his palace as a fortress he did not need.

And the water in front of you is the other half of the story. Francis wanted to tame the Cosson, the river that made this site a marsh, and even thought of bringing water from the Loire itself. It never happened. The straightening of the river began more than a century and a half later, under Louis the Fourteenth. In June 2016 the Cosson flooded into the moat, the château closed for six days, and for once it rose straight out of the water, the way its builder had imagined it.

Two floors up, and the reward is overhead. Tip your head back. Each arm of this cross-shaped hall is covered by a long, low, flattened vault, and the whole of it is divided into square stone coffers, eighty to a vault, every one carved in high relief. There are four vaulted arms. That is three hundred and twenty coffers, and almost all of them say one of two things.

The first is a letter: F, for Francis, sometimes crowned and sometimes not, framed in a cord tied in knots that make figures of eight. The knotted cord was the emblem of his mother, Louise of Savoy, and here it wraps round her son's initial again and again.

The second is an animal, the salamander. Find one. Some are spitting water, some are swallowing flame, and between them they act out the king's motto, nutrisco et extinguo: I feed on the good fire and I put out the bad. The estate reads the sheer repetition as a statement, a king determined to stamp his mark on every last ceiling of his keep.

Look closely and you may catch faint traces of gold and colour in the coffers. They are not from Francis's time. The vaults were gilded and painted in the eighteenth century, and a little of it has survived.

These vaults also work for a living. They carry the weight of the paved terraces directly above you, and they hold part of an ingenious system for getting rainwater off the roof. It did not always cope. Water got in and damaged the carving, and the first man to repair the château was Gaston d'Orléans, brother of Louis the Thirteenth, who had received Chambord with the county of Blois in 1626: the leaking terraces, the lantern tower and these sculpted vaults were all mended in his time.

This floor has had other lives. Maurice de Saxe, Marshal of France, was given Chambord by Louis the Fifteenth in 1745 as a reward for his victory at Fontenoy. He lived here, in the estate's words, as would a sovereign, with his own court and his regiments, and he set up a theatre on this second floor of the keep. He died in the château on the thirtieth of November 1750.

One more thing about where you are standing. Because the plan is a cross, the four apartments tucked into the corners of every floor of the keep are identical, so you could be on any side of the building and see the same thing. There is one more climb, and it comes out on the roof.

Walk to the garden side of the terraces and look out. This is what Chambord was built for: not a town, not a village, but forest, 5,440 hectares of it, the largest walled park in Europe, inside a wall 32 kilometres long. Francis the First put his palace in the game-rich marshes of the Sologne for the hunting, and over his whole reign he spent a mere fifty days here.

Find the straight line of water running away from the château into the trees. That is the Cosson, the river that made this ground a marsh, and it took well over two centuries to discipline it. From about 1684, under Louis the Fourteenth, earth was banked up round the château to lift it above the floods, retaining walls went up round the artificial terrace below you, and the river was straightened to follow its edge. Then the work stopped. What started it again was malaria. Stanisław Leszczyński, the exiled king of Poland and father-in-law of Louis the Fifteenth, lived here from 1725 to 1733, and in summer fever spread through his household. From 1730 the bridges, the dykes and the terrace walls were finished, the river was cleaned and widened into a canal, and a formal garden of six and a half hectares was laid out to a drawing of 1734. By 1751, in Maurice de Saxe's time, tubs along its paths held 250 pineapple plants, 121 orange trees, one lemon tree and one lime. Two centuries later it had been reduced to lawn, and in 2017 it was replanted to the eighteenth-century design.

Two stories from the Second World War belong to this view. In 1939 the Paris museums, the Louvre among them, sent their treasures away in convoys, and Chambord became the largest of the eighty-three depots that hid them: by June 1944 it held four thousand cubic metres of crates. The Mona Lisa arrived on the twenty-eighth of August 1939 with fifty other paintings and stayed only a few months. Delacroix's Liberty Leading the People and the Lady and the Unicorn tapestries were hidden here too. And on the twenty-second of June 1944 an American B-24 Liberator bomber crashed onto the château lawn. The works themselves came through the war unscathed.

The century before had been harder on the building. In the 1830s the American poet Henry Wadsworth Longfellow found it deserted: all is mournful and deserted, he wrote, and the grass has overgrown the pavement of the courtyard. Since 1930 the château and its park have belonged to the French state, and from up here you can take in everything that came with it: the palace, the canal, and all that forest, still inside one wall.