The Château de Chambord, built between 1519 and 1527 in Sologne, was one of the boldest projects of the young King Francis I. It stands on the banks of the Cosson River, at the centre of a network of canals, on game- and moisture-rich land. The château's architect remains unknown, but researchers believe Leonardo da Vinci was involved in the design. Several Italian specialists, including the hydraulic engineer Pietro Caccia and probably the architect Dominique da Cortona were involved in its construction.

With its central layout built around a square keep flanked by four round towers and its regular proportions, it is clearly inspired by Italian villas, but it also followed medieval traditions. On the façades, including the corner towers of the keep and the enclosure, order is reflected in criss-crossing patterns, with the floors divided horizontally and vertically by mouldings and pilasters. Its roof (after 1537) bristled with turrets and chimneys with polychrome geometric elements is reminiscent of French fortified castles in the late Gothic style with Italianate motifs. It is characterised by its finesse and virtuosity.

The interior of the keep is structured around the double helix staircase, the centrepiece of a theatrical mise en scène of life in the château. We have Leonardo da Vinci to thank for its design. The surrounding common areas are covered by three-centred barrel vaults with sculptured coffers. The presence of salamanders and the Royal Cypher highlights the power of Francis I. The king's apartments occupy the south wing of the enclosure, and in one of its towers his vaulted study is also decorated with coffers. The chapel on the opposite side was initiated in France by Sebastiano Serlio and constructed towards the end of the king's reign. Its architecture features Antiquity-inspired twin columns. In 1547, at the time of Francis I's death, the chapel wing and lower wings remained unfinished.

Surrounded by a huge forest, the château was an ideal place for hunting and for parties. On 18 December 1539 Francis I invited the Emperor Charles V to stay there, as well as many ambassadors, who were all most impressed by what they saw. To his contemporaries, and even today, the site embodied a kind of utopian city.