Harlech Castle in Gwynedd, Wales, is a Grade I listed medieval fortification built onto a rocky knoll close to the Irish Sea. It was built by Edward I during his invasion of Wales between 1282 and 1289. Over the next few centuries, the castle played an important part in several wars, withstanding the siege of Madog ap Llywelyn between 1294 and 1295, but falling to Prince Owain Glyndŵr in 1404. It then became Glyndŵr's residence and military headquarters for the remainder of the uprising until being recaptured by English forces in 1409.
During the 15th century Wars of the Roses, Harlech was held by the Lancastrians for seven years, before Yorkist troops forced its surrender in 1468, a siege memorialised in the song 'Men of Harlech'. Following the outbreak of the English Civil War in 1642, the castle was held by forces loyal to Charles I, holding out until 1647 when it became the last fortification to surrender to the Parliamentary armies. In the 21st century the ruined castle is managed by Cadw, the Welsh Government's historic environment service, as a tourist attraction.
UNESCO considers Harlech, with three others at Beaumaris, Conwy, Caernarfon, to be one of 'the finest examples of late 13th century and early 14th century military architecture in Europe', and it is classed as a World Heritage Site. The fortification is built of local stone and concentric in design, featuring a massive gatehouse that probably once provided high-status accommodation for the castle constable and visiting dignitaries. The sea originally came much closer to Harlech than in modern times, and a water-gate and a long flight of steps leads down from the castle to the former shore, which allowed the castle to be resupplied by sea during sieges. In keeping with Edward's other castles in the north of Wales, the architecture of Harlech has close links to that found in the County of Savoy during the same period, an influence probably derived from the Savoy origins of the main architect, James of Saint George.
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.