At Blaye, Vauban planned a new town wall with four bastions, three demi-lunes and two gates. He thereby transformed the medieval wall, systematically adapting the existing structures but leaving no visible outer signs of his work.
From the other side of the bank, the engineer had a square fort, Fort Médoc, built from scratch on marshy land, meaning that he could only build barriers of earth for defence.
Finally, Vauban erected Fort Pâté on an unstable sandbank in the middle of the river to close off the estuary. This oval canon tower was a remarkable technical feat and the prototype of a compact sea fort. It enabled cross fire with both banks, located 1600 metres from the island.
These three monuments, built on distinctly different sites, are complementary and today share a common cultural and tourism project.