It is a memorable experience to approach this pale granite fort standing in the waves from the sea. A first fort was built here in 1542 to protect Morlaix from English attacks. It was reworked by Vauban before being turned into a prison, then a sailing school. You can see the cannons, water cisterns and the rooms where soldiers and prisoners lived. The terraces offer magnificent views over the Bay of Morlaix and, in the distance, the towers of St-Pol-de-Léon Cathedral.