Although there are still questions that were not answered (probably never will be) the fact is that whoever built the pyramids had to be very skilled because even today, it would be very difficult to build such structures by using our modern technology. If the ancient Egyptians built the pyramids, we will probably never find out how they built them. If they were built by extraterrestrial civilizations, we have to wait until they come and explain to us their method of building.


(Checked by native speaker).