Schwanau island in Lake Lauerz is occupied by a ruined castle, a chapel and a restaurant. Traces of occupation on the island date back to around 1200 BC. There is little documentary evidence relating to the castle, but it is believed to have been built at the end of the 12th century and to have been ruined, probably as a result of a fire, as early as the middle of the 13th century.
The island in known to have been occupied by hermits at various times, including the 17th and 18th centuries. In 1684 a chapel was built on the island, but this was destroyed by the tsunami that followed the 1806 Goldau landslide. In 1808 the council of the church in Schwyz sold the island to General Ludwig Auf der Maur on the provision that he rebuild the chapel. The island remained in the possession of the general's descendants until 1967, when it was purchased by the canton of Schwyz. In 2009 it was completely renovated.
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.