When I visited Peru earlier this summer, I spent some time exploring Sacsayhuaman. What an experience! It was amazing to see the cyclopean walls; I was fascinated by the precision of the stonework. Many of the joints, which were on compound angles, were so tight that I couldn’t slide a blade of grass between them. I’m not sure what impressed me the most—the precise cuts and interlocking patterns, or the fact that these massive stones were moved great distances and put so perfectly into place.