Walls of Constantinople, Turkey
Built in the fourth and fifth centuries, these walls have surrounded their namesake city (now called Istanbul) for centuries. The first wall, built by the famous emperor Constantine, was a single structure with towers spaced an even distance apart. However, the city thrived in the following century and spread well beyond this original barrier. The Theodosian Walls, named after a later ruler, expanded the reach of the original wall. These newer walls have a number of gates and towers that still stand thanks to rebuilding efforts after strong earthquakes shook Istanbul.
Over the centuries, other walls were built to connect the earlier structures with Istanbul’s sea walls, which saw heavy combat during the Crusades of the 13th century. Some of Istanbul’s walls run right through the city center. These urban walls were restored in the 1980s and now sit side by side with modern buildings and roadways.