Both phases of the fort are built with small rectangular blocks, but massive stone blocks were used where the sea battery is exposed to the pounding of the waves, in an effort to prevent the erosion of the foundations. These large square blocks probably came from an ancient settlement (Nicopolis?). There are also various modifications in concrete, undertaken by the Germans in the Second World War. As you leave the fort, pay attention to the earth reinforcement along the external faces of the north, east, and west walls. It rises to half the height of the walls and was added sometime in the 19th century to protect the original walls.