Pyramids can be a primitive form of monumental architecture. Some say that there is nothing too impressive about them as they see it no more than a pile of big rocks, forming a basic geometric shape with some rudimentary architectural elements. Despite being a simple architectural form, and that anyone can do it, what is impressive about pyramids is the means to move heavy weights at those ancient times. In short, it's also very interesting that everybody stopped building pyramids as soon as the Romans invented cement, which made possible building tall walls using bricks first, which are cheap to manufacture and move around.
