Looking over ruins in the upper sector of the city, which was largely used for residential and worship purposes. On the right are the huge terraces built by the Incas which was used for agriculture. It is believed that the Incas constructed these terraces, fortified through rock walls, to (1) stabilise the hill and to (2) create the different conditions necessary to grow different crops (for example, there has been up to a 60 fahrenheit degree difference recorded in the temperature between ledges at the top and bottom of one of these terraces).