As elsewhere, Incan farmers used every bit of available soil for crops. Their use of terraces built on steep slopes is still in use today by their descendents. The terraces, built of stone walls holding back layers of rock, sand and finally fertile soil from the river banks below, were not only agricultural but structural. They helped hold the city in place by preventing the buildings from sliding down the steep slopes. Inca farmers grew maize, what we know as corn, potatoes and even avocado trees.
The city area was zoned into sectors. The agricultural terraces, and an urban sector, itself divined into west and east zones. the west zone had the plazas, temples, and the royal quarters, called the Kings Group. The east side of the urban sector was guest quarters, and home to the architects who designed the city.