Just so you know, absolutely none of that is true.
https://en.wikipedia.org/wiki/Pyramidion_of_Amenemhat_III
I don't know if the person who posted that is sincere or not, but plenty of people sincerely believe this sort of thing when it is posted on Facebook.
It's almost as if they are racists that believe no one but white people can build amazing architecture using complex mathematics and expert engineering with proper planning and enormous budgets.
Racism certainly plays a big part in the whole Atlantis/Ancient Aliens thing. When it was introduced by Madam Blavatsky, it was more blatant, but it's less so now, and the believers probably don't even think about it consciously.
But, as Milo "Minuminuteman" Rossi has pointed out in his debunking videos, the only European monument they can't believe that people didn't build was Stonehenge.
Or perhaps instead of race they’re timeists who think that before invention of modern technology it would have been hard to do such things.
I mean, it would have been much harder than with modern technology, but it's not impossible.