Solomon's Stables was an underground vaulted space now used as a Muslim prayer hall at the bottom of stairs which lead down from the al-Aqsa Mosque, under the Temple Mount, to the base of the southern wall of the Temple Mount. Solomon's Stables are located under the southeastern corner of the Temple Mount, 12½ metres below the courtyard and feature twelve rows of pillars and arches. In December 1996 the Jerusalem Islamic Waq (an Islamic religious trust) converted the area into a prayer hall by adding lights and floor tiles, and renamed it the Marwani Prayer Hall.
The structure is most widely said to have been built by King Herod as part of his extension of the platform of the Temple Mount southward onto the Ophel. The Herodian engineers constructed the enormous platform as a series of vaulted arches in order to reduce pressure on the retaining walls. These vaults were originally storage areas of the Second Temple. A great deal of the original interior survives in the area of the Herodian staircases, although not in the area now renovated for use as a mosque. Visitors are rarely permitted to enter the areas with Herodian finishes.
The underground space for the most part remained empty except for the Crusaders period. The Crusaders converted it in 1099 into a stable for the cavalry. The rings for tethering horses can still be seen on some of the pillars. The structure has been called Solomon's Stables since Crusader times as a historical composite. 'Solomon's' refers to the First Temple built on the site, while the 'stables' refers to the functional usage of the space by the Crusaders in the time of Baldwin II (King of Jerusalem 1118-1131 CE).
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.