The Ursuline Monastery of Quebec City was founded by a missionary group of Ursuline nuns in 1639. It is the oldest institution of learning for women in North America. Today, the monastery serves as the General Motherhouse of the Ursuline Sisters of the Canadian Union. The community there also operates an historical museum and continues to serve as a teaching centre.
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.