Church of San Andrés is an impressive church built in stone in the 16th century. In the same building, several architectural styles are to be seen, from the gothic to the neoclassical and the renaissance. The most Gothic parts are the nearest to the towers. It's the only remaining part of the Gothic building over which the current building was erected. Picturesque columns and archs. In the other part of the church we can see the sacristy, in neoclassical style. In the middle part we can see the stylistic evolution in the building. In the 'crucero' part we can see a Renaissance style. The church has also a baroque and renaissance-style altarpiece. The 18th-century organ, of classical style, is still in use and used for concerts.
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.