The New Fortress of Corfu is a Venetian fortress built on the hill of St. Mark in Corfu. The current buildings which exist within the fortress were built by the British during their rule of the island (1815–63).
In the aftermath of the first great Ottoman siege of Corfu in 1537, the Venetians developed plans to expand the fortifications of the city. Venetians built the New Fortress at the hill of St. Mark to further strengthen the defences of the outer city of Corfu and to act as the focal point of the new fortifications. The exact dating of the structure is not established but accounts vary between 1576 or 1577-1588, and 1572-1645.
The sea defences of the New Fortress were destroyed by the British when the British protectorate came to an end and Corfu was united with Greece in 1864. Under the same agreement, the Avrami and Vido island forts were also destroyed. When the latter fort was demolished, the explosion was so strong that it broke house windows on the Corfu side of the sea channel.
At the top of the castle there is a stone building which was used for defence and a brick building which in modern times functions as the headquarters of the Naval Station of Corfu. The Venetian fortifications were later expanded by the British and the French to help defend against a possible Turkish attack. Its fortifications included 700 pieces of artillery with range estimated as far as the Albanian coast.
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.