Great thread, this is one subject that just kills the Bible and taking it literally. According to the JWs timeline the pyramids at Giza had to be built before the flood. Even if they could some how argue this way there's one issue they can't. Mizraim, the patriarch of Egypt according to the Bible. But wait there literally a thousand years of Egyptian kings before this guy written in stone and on the Turin list as well as several temples in Egypt. These kings most have been confirmed by archaeologists. That's again one thousands years of Egyptian history and kings before the grandson of Noah came on the seen.
We also need to remember (if the JWs are correct) after they were all killed by the flood Noah's grandson moved to Egypt had kids and his offspring picked up right were the Egyptians left off , building the same way , worshiping the same gods, making the same kind of temples , dressing the same , and then built more pyramids, the same way.