Aliens or god
Everybody knows the Bible story about the origin of the human race.
The god Jehova, created a man named Adam and a woman named Eve and placed them in a garden called Eden. This is an ancient story shared by both the Jewish and Christian religions. It appears in Genesis, the first book of the Old Testament.
I suspect this story is a twisted version of what really happened. Because of personal contact with aliens in parallel but multidimensional universes, I know that we three-dimensional humans are not alone. We never have been alone. We are surrounded by intelligent life that sometimes enters our dimension and frequently manages to influence our way of life.
While I cannot prove it, I suspect that one or more alien cultures came to Earth in the distant past and used some form of genetic engineering to alter the brains of existing animals, giving them what we know today as human consciousness. This would explain the sudden rise of great civilizations. It also would answer the riddle behind the construction of complex cities and stone monuments by a people that just crawled out of a cave-life existence.
How would humans have the sudden ability to hunt, farm, build monuments, and worship a god unless they were suddenly created (i.e. genetic manipulation) and also given personal instruction by another intelligent life form. Our apparent need to constantly worship something, whether it is a rock or an invisible deity in the sky, might stem from this kind of mental conditioning.