Mussenden Temple is a small circular building located on cliffs near Castlerock in County Londonderry, high above the Atlantic Ocean. Perched on the cliffs overlooking Downhill Strand, it was once possible to drive a carriage around the temple: however, coastal erosion has brought the edge closer to the building. The temple was built in 1785 and forms part of the Downhill Demesne. The demesne was formerly part of the estate of Frederick, 4th Earl of Bristol, who served as the Church of Ireland Lord Bishop of Derry from 1768 until 1803. It was Lord Bristol – popularly known as 'the Earl-Bishop' – who had the 'temple' built. Constructed as a library and modelled from the Temple of Vesta in the Forum Romanum in Rome, it is dedicated to the memory of Bishop Lord Bristol's cousin Frideswide Mussenden.
Now part of The National Trust property of Mussenden Temple and Downhill Demesne, the grounds encompassing Mussenden Temple, and its manor house (Downhill Castle) are open to the public all year, from dawn to dusk.
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.