Some scientists think that the pyramids are towers that were used to communicate with aliens. This type of episode was aired on nat geo channel.
LOL, they are not scientists. Most of them are just writers and a few fringe professionals. That idea has been debunked too, it's just pseudo-scientific stuff. Of course, History Channel airs it because, contrary to appearances, they really aren't committed to science popularization. They need to sell and sensationalism sells well.