Medina Azahara ('the shining city') is the ruins of a vast, fortified Andalus palace-city built by Abd-ar-Rahman III (912–961), the first Umayyad Caliph of Córdoba. Located on the western outskirts of Córdoba, it was the de facto capital of al-Andalus as the heart of the administration and government was within its walls. In 2018, the site was listed as a UNESCO World Heritage site.
Built beginning in 936-940, the city included ceremonial reception halls, mosques, administrative and government offices, gardens, a mint, workshops, barracks, residences and baths. Water was supplied through aqueducts. The main reason for its construction was politico-ideological: the dignity of the Caliph required the establishment of a new city, a symbol of his power, imitating other Eastern Caliphates.
The complex was extended during the reign of Abd ar-Rahman III's son Al-Hakam II (r. 961-976), but after his death soon ceased to be the main residence of the Caliphs. In 1010 it was sacked in a civil war, and thereafter abandoned, with many elements re-used elsewhere. Its ruins were excavated starting from the 1910s. Only about 10 percent of the 112 hectares have been excavated and restored. A new museum on the edge of the site has been built low, with much of the space underground, to minimize disruption to the views of the landscape from the ruins, which are also beginning to be affected by modern housing.
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.