Sablanceau and Redoute of Rivedoux, Military redoubt in Rivedoux-Plage, France.

Sablanceau and the Redoute of Rivedoux form a square-shaped fort with each side measuring 45 meters, featuring artillery positions and barracks buildings. Inside, a well and underground storage chambers were built to support extended occupation by military personnel.

Built in 1674 under Vauban's direction, this fort was constructed in response to the 1627 English invasion when 6,000 soldiers landed on the beach. Later modifications came during Napoleon III's reign in the 1860s, and it subsequently served German forces during World War II.

The beach takes its name from Saint-Blanceau, its old form; the redoubt is named after Rivedoux-Plage. Vauban called this post the most exposed in the whole kingdom, more important to the island than any but Saint-Martin-de-Ré. The municipality bought the redoubt in 2005 and volunteers now open it for visits and exhibitions.

The redoubt stands on the Sablanceau point at the eastern tip of Île de Ré, in Rivedoux-Plage; the municipality bought it in 2005 and volunteers opened it for visits and exhibitions. The dry moat on the entrance (west) side has been filled in and a campsite now occupies the glacis. The neighbouring Sablanceau battery, under 500 m away, cannot be visited and is ringed by barbed wire.

During World War II the occupying German army fitted an observation blockhouse inside the south guardhouse, hidden from outside view, and built a battery on the south counterguard. The entrance ditch on the west side was later filled in and a campsite set up on the glacis.