Bourtzi is an island fort, located off the coast of Nafplio, in Greece. It is an incredibly imposing structure that was originally part of the city's defenses, connected to the mainland by thick chain walls to prevent enemy ships from docking or getting close.
Built by the Venetians in the 15th century once they realised the strategic importance of this small and unassuming island, located right by the port of Nafplio, it is on an imperfect hexagon plan that matches the shape of the island itself. Perfectly in tune with its setting, it is a picturesque and extraordinary building.
Pirates were, initially, the primary concern but it was to the Ottoman Turks that the fortress fell in 1715. Once in control, they fortified the building further and dropped big rocks into the waters nearby, ensuring that no ships or big boats could get close.