Tikal
During our trip to Belize, Danny and I took a day long excursion to Guatemala. Our goal was the ruins of the Mayan city of Tikal. The city was at its peak from 700 to 900AD. The population within the earthworks defenses (16 sq. mi.) was estimated to be as high as 90,000. Outside the defenses, the people spread and populated an area with a 16 mile radius. Within this area, the population was approximately 425,000! It was one of the largest cities in the Americas.