In addition, from the point of view of comparative world history, 6000-7000X year-old city sites have been discovered in Egypt, Central Asia, and India, but most of these were mud-brick cities or stone cities. There are few cases of city walls built using mud as a construction material.
此外，從世界文明史看來，在埃及、中亞、印度等地區，距今六、七千年的城址迭有發現，但多是泥磚或石頭城，像城子崖一樣以泥土為材料造成的城牆，並不常見。