Various Pyramid architectural style

Here is a link to a video in youtube on "Cambodia, Prasat Thom pyramid".
http://world-pyramids.com/en/video/cambodia,-prasat-thom-pyramid.html

Another link to a history channel on ancient pyramid. It shows a lot of different styles of architect on the pyramid from Asia, Europe, Middle-East & the American continent.
http://world-pyramids.com/en/video/secrets-of-the-pyramids.html

Below are some of the world's various pyramid architecture. They all have a different flavours but basically, they all have a square base for a firm foundation.

Cambodia:

Egypt:

Indonesia:

Mexico:

Mexico: