Step pyramid

A step pyramid or stepped pyramid is an architectural structure that uses flat platforms, or steps, receding from the ground up, to achieve a completed shape similar to a geometric pyramid. Step pyramids – typically large and made of several layers of stone – are found in several cultures throughout history, in several locations throughout the world, with no known connections between the different civilizations that built them. These independent adoptions of a similar design presumably emerged at least partly because step pyramids have a lower center of mass than would a structure with straight vertical sides and are thus inherently more stable.