Advanced ancestors

The other day me and my colleagues were having an interesting talk. We were discussing about the Egyptian pyramids and how perfect they were. I was watching this show on the History Channel a few months back which discussed how aliens might have helped build the pyramids. The pyramids are actually aligned based on stars or some zodiac (I am not sure which one though), but the mysterious part is they are not even off by an inch. How could the Egyptians build something so perfect with tools that were available during those times. Those stone slabs must be weight tonnes. How did they carry those at such an height? Did they have cranes? So one of my colleagues said that may be the technology they had in those times was far more advanced than what we have today. And then something must have happened and would have wiped the entire civilization away, taking away all the tools and techniques along with it. Thus we start at the very beginning. This sort of makes sense, but what really struck me were the following arguments by other colleagues. They were like during the time of Mahabharata, they had wireless technology and test tube babies. The backed it up by saying how could Sanjay (chariot rider for king Dhritrashtra) could tell him what happened in the battlefield of Kurukshetra without even being anywhere near it. The test tube babies were explained by the fact that Gandhari, wife of the King Dhritrashtra, had 100 children which came all at once. So I was a little stumped and this has raised this question in my mind. Could our ancestors be so much more advanced than what we are today? Does everything really get wiped out? When will we get wiped out?