Who built the pyramids?
As though modern reenactors and scientists have not fought over the solution of the riddle of the construction of the pyramids, convincing versions of the method of their construction have not been found so far. Some experts say that the pyramids were built of prefabricated blocks, hewn in the rock, others (Joseph Davilovitz) say that the blocks were already made at the construction site from a mixture of stone crumbs and "geopolymer concrete" based on limestone. The incredible laboriousness of the process casts doubt on all hypotheses. The question remains as to who built pyramids, slaves or civilian workers, and how many there were.
Where did the Maya go?
The Mayan civilization was one of the most developed, but by the time the conquistadors arrived from the Maya, only scattered forest tribes, underdeveloped and not representing a serious force, remained. They lived in huts and did not build majestic temples with palaces. Where did the Maya disappear? The riddle is still not solved. There are many versions, from epidemic and war to extraterrestrial intervention, but none of them is proven.Who were the Sumerians?
The world community learned about the Sumerians only in the middle of the XIX century, when scientists proved that there was a state in the Mesopotamia, whose age reaches 6000 years. It was from him that Babylon and Assyria inherited their culture. It is still unknown where the Sumerians came to Mesopotamia. It is assumed that this was a mountainous region, because in the language of the Sumerians, the words "country" and "mountain" are written in the same way. It also had to be a terrain with advanced technologies - the Sumerians were pioneers in many areas of knowledge, from astronomy to physics. Presumably, but not yet proven that it could be the south of India.