It's thought that these 1.2 square miles of walls took about 10,000 men 12 years to build. So what I do know is that they had some type of organized government and they could get slaves and they could get peasants to do stuff like build those walls to protect the upper class who lived in timber framed houses. They were living like gangsters back then. And outside the walls, bum bum bum bum, that's where the peasants and the artisans lived. They lived in these little hovels and they scattered around for food. So a very strict social class system is evident from the Shang Dynasty. We also know that military and defense was very important to the Shang Dynasty.