Come and visit Fort Louvois, a 17th century coastal fort built on a submerged rock between Oléron Island and the Marennes Basin.
It was built from 1691 to 1694 according to plans drawn up by Vauban, the famous military engineer who served under Louis XIV. Taking the form of a horseshoe-shaped outer wall with a central tower protected by a drawbridge and moat, the fort is reminiscent of a medieval castle.
Fort Louvois was designed to protect the southern approach to the Charente estuary by catching enemy ships in a crossfire with the citadel at Oléron. This prevented an enemy from sailing up the river to attack the naval dockyards at Rochefort.

At low tide, the fort is connected to the mainland by a 400-metre long causeway.
At high tide, a free shuttle boat is available (in summer only).