Siega Verde is an archaeological site in Serranillo, Villar de la Yegua. It was joined to the Côa Valley Paleolithic Art site in the World Heritage List in 2010.
The site consists of a series of rock carvings, discovered in 1988 by professors Manuel Santoja, during an inventory campaign of archaeological sites in the valley of the Águeda river. Subjects include equids, aurochs, deer and goats, among the most common ones, as well as bison, reindeer and the woolly rhinoceros, which were not yet extinct at the time.
The engravings date to the Gravettian culture of the Upper Palaeolithic (circa 20,000 years ago). There are also more recent, anthropomorphic representations, dating to the Magdalenian age (c. 9,000 years ago). There is a total of 91 panels, spanning some 1 kilometers of rock.
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.