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 city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.