The Keep that refuses to drown

The Château de Sully-sur-Loire, situated in the commune of Sully-sur-Loire, Centre-Val de Loire, France, is a château-fort, a true castle, built to control one of the few sites where the Loire can be forded. It sits on the south side at a natural fording point of the Loire, at the confluence of the Loire and the River Sange. Originally, it was built on the Southwestern island, but the Northwestern island later housed the main keep. The château was built with defenses on various islands and was initially open to the Loire, but dikes have been constructed to limit flood damage.

The Southwestern island now houses the Inner Courtyard, with its defense towers, galleries, and later residences, while the Outer Courtyard, now regularised, has been empty since history. The outdated details of the original layout and first historical reference have been rephrased to fit better with the remaining content.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons