There are a more than a few temples located within this city. The Sun Temple, in particular, is one of the most powerful.  A nearby steep mountain peak was scaled by the Inca so that they could chisel out a profile of a face. On the winter solstice (June 21 in the southern hemisphere), the sun aligns directly with the eye of the profile through a window across the valley at the ruins and onto an altar.  No less stunning is the fact that all the rock used for the terracing at Ollantaytambo was quarried from a mountain top on the opposite side of the valley 6km away. The "so called" scientific theory would lead you to believe that the drug them down this steep hill, across this roaring river and then uphill to the top of this magnificent city.  By the way,they were set into place so perfectly that mortar is not necessary. The engineering of this civilization was extraordinary.