In our days in Peru so far, we have visited numerous Inca sites. Machu Picchu, of course, is the ne plus ultra of the Incas: it is truly a wonder. But there is a site nearby, named Wiñay Wayna, that to us at least, is just as captivating. Built in the 15th century, it is cut into the steep, concave hillside. The curving terraces feel as if you have been floated into space. The environmental harmony with which the Incas lived is manifest.
The purpose was agricultural, so the housing was for the middle class workers who tended the terraces. This is in contrast to the function of Machu Picchu, which was a palace for the king, which then excluded everybody else.
Wiñay Wayna is on the Inca Trail. And the only way to get there is on foot, up or across challenging mountain terrain. Which means that there are blessedly few tourists. Maybe the real reason we liked it so much was because there were no fleets of tour buses idling in a parking lot below.