The Royal Chateau at Chambord, Loir-et-Cher, France, is one of the most recognizable castles in the world because of its very distinct French Renaissance architecture that blends traditional medieval forms with classical Italian structures.

It is the largest château in the Loire Valley, but was built to serve only as a hunting lodge for King François I who maintained his royal residences at Chateau Blois and at Chateau Amboise. The original design concept for Chateau Chambord was made by Domenico da Cortona, but was altered considerably during the twenty-year construction between 1519 and 1539. Leonardo da Vinci, a guest of King Francois at Close Lucé near Amboise, is believed to have been involved in the original design. Nearing completion, King François showed off his enormous symbol of wealth and power by hosting his old enemy, Emperor Charles V. .

The massive chateau features 6 immense towers, 440 rooms, 365 fireplaces, and 84 staircases. Four rectangular vaulted hallways on each floor form a cross-shape, meeting in the center. One of the architectural highlights, and very popular with the general public, is the spectacular double-helix open staircase where people can ascend and descend at the same time without ever meeting.

The chateau is surrounded by a 13,000 acre wooded park and game reserve filled with Red Deer enclosed by a 32 kilometre (20 mile) wall.

After King François died, during the next 80+ years future kings all but abandoned the chateau, allowing it to fall into decay. Finally, in 1639 King Louis XIII gave it to his brother Gaston d'Orleans who saved the chateau from ruin by carrying out much restoration work. King Louis XIV had the great donjon restored and furnished the royal apartments. The king then added a 300 horse stable enabling him to use the chateau as a hunting lodge and a place to entertain such notables as Moliere for a few weeks each year. Nonetheless, Louis XIV abandoned the chateau in 1685.

From 1725 to 1733, Stanislas I (Stanislas Leszczynski), the deposed king of Poland and father-in-law of King Louis XV lived at Chambord. In 1745, as a reward for his fighting valor the king gave the chateau to Maurice de Saxe, Marshal of France who installed his military regiment there. Maurice de Saxe died in 1750 and once again the colossal chateau sat empty for many years.

In 1792, the Revolutionary government ordered the sale of the furnishings and the empty chateau was left abandoned until Napoleon Bonaparte gave the château to French military leader Louis Alexander Berthier whose widow sold it to the Duke of Bordeaux, who then took the title Comte de Chambord. A brief attempt at restoration and occupation was made by King Charles X (1824-1830) but little was done and during the Franco-Prussian War, (1870-1871) the chateau was used as a field hospital.

The final attempt to make use of the colossus came from the Comte de Chambord and his offspring but after the Comte died in 1883, the chateau was left to the Ducal family of Parma, Italy. Any attempts at restoration ended with the onset of World War I in 1914. The chateau became the property of the Government of France in 1930 but restoration work was not begun until a few years after World War II ended in 1945.

Today, it is a major tourist attraction.