The Spanish Fortress dominates the historic centre of Porto Santo Stefano in the municipality of Monte Argentario.
The building was constructed in the early 17th century to defend the port and the town from pirate attacks.
Today it houses two permanent exhibitions: the Museum of Axe Masters and the “Memorie Sommerse” – or “Submerged Memories” exhibition.
Both exhibitions follow the evolution of underwater archaeological exploration, from its dawn to modern technologies.
The Spanish Fortress, with its 500 square metres of exhibition space, houses a number of artefacts, mostly of Roman origin, that were found on the sea bed surrounding the islands of Giannutri and del Giglio, and along the coast of Argentario.
There is also a section on the discovery of a wreck dating to the 7th century B.C., and two halls containing demographic materials that stand witness to the ancient art of shipbuilding.