A building lost in the midst of a 5 000 hectare park, that's the equivalent of the surface of Paris, Chambord is the castle of all superlatives. Having required nearly 220,000 tonnes of stone to build, the Chateau de Chambord, in the Loir-et-Cher department, is an architectural gem. 156 metres of facade, it has more than 70 staircases, 282 fireplaces and 426 rooms. The castle commissioned by Francis 1st in the 16th century is also the most mysterious. The majestic monument has its share of mysteries: identity of its architect, influence of the Florentine painter Leonardo da Vinci in its design, location in the middle of marshes in the heart of the forest and even longevity because it has survived through time without being damaged since the beginning of its construction in September 1519.