According the tradition, after the Meshica (aztec) leave Aztlan, they wandered for two hundred years, seeking a signal sent by their god Huitzilopochtli: An eagle on the top of a Cactus. And finally they found it..
In the middle of a lake, in a small Island.!!
So, they built a great artificial Island around it.
Now... the Texcoco lake is a system of Endorheic lakes.. which means, no only that the city suffered form periodic inundations, but that the water was a bit salty , so there was the problem of getting fresh water for the city. They built a system of dams to separate the water of the lake in salty and fresh water. and control the level of water.
charming isn't it?
After the conquest, the Spaniards dried the lake, son now... Mexico City suffers form lack of water
Many Mexican Urbanists have confessed they have dream the travel to the past, with some stones at hand.. to sent that damn eagle to a better place.!!
In the three hundred years of aztec ruling, the amount of deaths by sacrifice was lower than the death toll in just one day on hiroshima.
who is the mass murder?
A complex system that works is invariably found to have evolved from a simple system that works.