Graham Hancock on Twitter: "The giant megaliths of Puma Punku bear witness to an immense task carried out in remote antiquity by unknown hands at an altitude of almost 13,000 feet above
Tiahuanaco Monuments (Tiwanaku / Pumapunku), Bolivia are made of geopolymer artificial stones created 1400 years ago. – Geopolymer Institute
Semi-subterranean Court at the site of Tiwanaku (article) | Khan Academy