Circa 10.600 B.C.E or 12.600 years ago. The entire complex was built for a period of approximately 100 years.

It was built by the local people. The area then was similar to United States today in that it was a melting pot of many cultures.

Why? As a gravestone. These people knew their civilization would end and while many projects were to act as time capsules this one was built as a sort of memorial. In its vicinity were and still are records and caches of artifacts.

How? They used a principle of magnetism to effectively levitate the stones, onto ships from the quarry and then onto their place. They also use a chemical substance to soften the stone for ease of cutting.

Both the substance and the devices used were relatively simple appliances.