Castle of the Royal Force

The Castillo de la Real Fuerza is a bastion fort on the western side of the harbour in Havana, Cuba, set back from the entrance, and bordering the Plaza de Armas. Originally built to defend against attack by pirates, it suffered from a poor location; it was too far inside the bay. The fort is considered to be the oldest stone fort in the Americas, and was listed in 1982 as part of the UNESCO World Heritage Site of "Old Havana and its Fortifications".

Source: Wikipedia