The royal Château de Chambord is one of the most recognizable châteaux in the world because of its very distinct French Renaissance architecture which blends traditional French medieval forms with classical Renaissance structures.
The building, which was never completed, was constructed by King François I in part to be near to his mistress the Comtesse de Thoury, Claude Rohan, wife of Julien de Clermont, a member of a very important family of France, whose domaine, the château de Muides, was adjacent. Her arms figure in the carved decor of the château.
Chambord is the largest château in the Loire Valley; it was built to serve as a hunting lodge for François I, who maintained his royal residences at Château de Blois and Château d'Amboise. The original design of the Château de Chambord is attributed, though with several doubts, to Domenico da Cortona. Some authors claim that the French Renaissance architect Philibert Delorme had a considerable role in the château's design, and others have suggested that Leonardo da Vinci may have designed it.
Chambord was altered considerably during the twenty years of its construction, (1519–1547), during which it was overseen on-site by Pierre Nepveu. With the château nearing completion, François showed off his enormous symbol of wealth and power by hosting his old archnemesis, Emperor Charles V at Chambord.
The château is surrounded by a 52.5‑km² (13,000‑acre) wooded park and game reserve maintained with red deer, enclosed by a 31‑kilometer (20‑mile) wall.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.