The Guaita fortress is the oldest of the three towers constructed on Monte Titano, and the most famous. It was built in the 11th century and served briefly as a prison. It is one of the three towers depicted on both the national flag and coat of arms. It was registered as one of the World Heritage Sites in 2008.
Guaita was rebuilt in the second half of the 15th century and in the 16th century has been covered with a sloping roof. It is called the Rocca Guaita and, within its solid walls, protected by double walls (the external wall with merlons and truncated towers at the corners), the population found refuge during sieges.
The upper entrance door, which can be reached by a staircase, is protected by a small wooden construction of 1481. The courtyard contains some pieces of artillery from the Second World War: two mortars, a gift from Vittorio Emanuele II, two 75mm canons fired by the Guardians of the Rocca during national festivities, a gift of Vittorio Emanuele III.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.