Situated next to Cusco in the Inca heartland of Peru, Sacsayhuaman is one of the most incredible ancient structures in the world. It’s truly mind-boggling how such enormous blocks of stones can be so randomly shaped yet so perfectly put together. The origins of the megalithic blocks of Sacsayhuaman, Peru, have long been a source of debate because it really feels like a genuine mystery.

These are large blocks of limestone, sometimes huge, most of which seem to pillow or bulge out instead of having straight, sharp cut faces. Some blocks seem to curve around corners, others have scoop marks on the surface and a number have the famous nubs. There are many other seemingly bizarre and unnatural features. Each block is irregular and each is unique yet the joints between these limestone blocks are perfect. So how is this even possible?

I’ve speculated in the past that maybe some kind of stone softening agent was applied, possibly some kind of acid. At the end of the day, we can stare at pictures and speculate forever; what we have to do is look at the science. I’ve always said that samples need to be taken and the geology needs to be analysed and that will tell us everything we need to know about Sacsayhuaman.

Well, little did I know that such investigative work was done back in 2012 and in this study and take a detailed look at the geology of the blocks of Sacsayhuaman and so, once and for all, we should be able to answer the question - are they artificial geopolymer or natural rocks? This video is the geological truth of Sacsayhuaman.