How did geography protect constantinople from invasions?

Constantinople was strategically located on the Bosporus Strait, which served as a natural barrier against invasions, as it connected the Black Sea to the Mediterranean. The city's formidable defensive walls, including the famous Theodosian Walls, further enhanced its protection. Additionally, its position on a peninsula allowed for control over maritime routes, making naval assaults challenging. Together, these geographical features made Constantinople one of the most defensible cities of its time.