This building forms the third corner of the Sacred Square and is composed of enormous horizontal stones hewn from bedrock. The temple faces Cerro Machu Picchu and has an enormous altar on the back wall. Above the altar are very high niches where ceremonial items were placed.

The damage sustained to the stonework is due to insufficient foundations (an uncommon problem at Machu Picchu, where an estimate 80 percent of all stonework is underground and used to shore up the buildings on extremely steep and uneven ground).

Directly in front of the temple is a rustic house, believed to have been the house of the priest. Leaving the main square, going west behind the Principal Temple, you will come to a small construction on the right-hand side known as the Sacristy.

The Sacristy is the only room within the city that has the Inca imperial style but that is not a temple or a palace. If you look carefully, you may notice the anti-seismic construction using bedrock, keystones, and the famous 32-sided stone. Also note the unfinished polishing on the rocks.

Leaving the Sacristy, go to your right and climb up the impressive stairway to the top. On your right-hand side, there is a rock that represents the mountains of Putucusi and Yanantin, having the same exact form. Continue upwards to the home of the Intihuatana.