Protection was one of the most significant challenges that any nation in the past had to deal with. the answer was straightforward because countries—or rather, empires—did not have access to the same kinds of technologies that we do today. many cities had walls built around them to stave off sieges. this also applied to istanbul, or constantinople as it was formerly known. the constantinople walls were actually so strong that it took hundreds of years to breach them. as a reminder of the intricate and frequently bloody history of the city itself, the walls of constantinople are currently one of the most popular and significant sights in the city.