The Quechua people used no mortar here, and did not even know of the wheel, and yet made walls more resistant to time and earthquakes than their colonial conquerors could. They had no iron, no drills, yet perfect, rounded holes and immaculately chiseled stones abound. Boulders weighing hundreds of tons were dragged miles from their original resting places, sometimes up mountains. All of this has led some to consider aliens. I consider aliens. That seems like a cop-out.