37(d) No mortar required, can’t fit a needle into the joints!
Source: http://www.world-mysteries.com/mpl_9.htm “The stones fit so perfectly that no blade of grass or steel can slide between them. There is no mortar. They often join in complex and irregular surfaces that would appear to be a nightmare for the stonemason.”
Source: http://www.cusco.info/saqsaywaman.htm “Located 2km from the city (Cuzco). Together with the city of Cusco, this monumental complex is considered the first of the new seven wonders of the world. This huge construction was planned and built by Andean Man. The Incas called it the House of the Sun and the Spaniards called it a fortress because of its zig-zag shape and the 1536 revolution. The construction, which is made up of three platforms one on top of the other, was one of the most important religious complexes of its time.”
Source: http://www.britannica.com/EBchecked/topic/23548/Andean-peoples About Andean man: “Although human occupation began over 20,000 years ago, the beginnings of agriculture and population growth are much more recent. Within the last 8,000 years a specialized desert-and-highland agriculture was developed.”
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