 The third largest pyramid in the world, the Pyramid of the Sun, at Teotihuacan is also located in Mexico.There is an unusual pyramid with a circular plan at the site of Cuicuilco, now inside Mexico City and mostly covered with lava from an eruption of the Xitle Volcano in the 1st century BC.There are several circular stepped pyramids called Guachimontones in Teuchitlán, Jalisco as well.