The ancient city of Teotihuacan, just outside Mexico City, was built between about 200 and 700 AD, and was the sixth largest city in the world for some of that time, with 100,000 to 200,000 inhabitants. This is the view from the top of the Pyramid of the Moon, looking down the main street of the city, with the Pyramid of the Sun in the middle distance on the left (which is about the same width as Egypt's "Great Pyramid", though about half the height). By Aztec times, the city was a mysterious ruin that the Aztecs called "The City of the Gods", because they had no memory of the people who built it.