15. The Original Walls Are Sturdier Than Modern Repairs
In an incredible testament to ancient architecture, many of the walls of Constantinople still stand today. In the late 20th century, the UNESCO world heritage organization decided to attempt a restoration of portions of the wall that had lapsed, trying to recreate the ancient look. Ironically, an earthquake leveled the 20th-century repairs while leaving the old walls intact. It was later found that poor materials and methods were used in the modern maintenance.