Henry IV wanted to build a fortress to protect Saint-Jean-de-Luz and Ciboure from the Spanish invasions but it was Louis XIII who built Fort Socoa which guards access to the bay of St Jean de Luz and protects the small port of Ciboure from the waves of the Atlantic.
In 1636 the Spanish invade the Basque coast and pursue work that will be reinforced later by Vauban on the ruins left by the Spanish after the war of 30 years.
To go to Fort Socoa, follow the port of Ciboure and get to Socoa beach.