Cádiz is known worldwide for its watchtowers. They are witness to the trade and prosperity which the city experienced in the 18th century. At this time, the Tavira Tower the official watchtower of Cádiz due to the fact that it is situated in the centre of town, and was also the highest point in the town at 45 meters above the sea level.
Don Antonio Tavira was the first watchman of the tower and used his telescope to see the ships full with goods coming from America. Today the Camera Obscura enables us to observe Cádiz and its development in the 21th century.
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.