This is in line with my (admittedly not well researched) theory of why 'many primitive cultures built pyramids': a square-based pyramid is the most stable struc

This is in line with my (admittedly not well researched) theory of why 'many primitive cultures built pyramids': a square-based pyramid is the most stable structure that you can build to be really high. Columns, arches and metalworking are the things that allowed us to come up with something else, right?