Saint Nicholas Cathedral (officially Cathédrale Notre-Dame-Immaculée) is the cathedral of the Roman Catholic Archdiocese of Monaco, where many of the Grimaldis were buried, including Grace Kelly and more recently, Rainier III.
The cathedral was built in 1875-1903 and consecrated in 1911, and is on the site of the first parish church in Monaco built in 1252 and dedicated to St. Nicholas. Of note are the retable (circa 1500) to the right of the transept, the Great Altar and the Episcopal throne in white Carrara marble.
Pontifical services take place on the major religious festivals such as the Feast of Sainte Dévote (27 January) and the National holiday (19 November). On feast days and during religious music concerts, one can hear the magnificent four-keyboard organ, inaugurated in 1976.
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.