Catal Hüyük, in modern-day Turkey, was one of the first cities to be founded, in around 7500 B.C. Catal Hüyük didn’t have streets, and all the houses were bunched together. So if someone wanted to get to a house located at the center, they’d have to climb over the ones at the periphery. The city didn't have places to gather and there were no public squares either. The city flourished for about 1,000 years, primarily because of the trading of a volcanic stone called obsidian.