Structure B1-1 is believed to have developed from a central temple and platforms on each side in the cardinal directions, with the west platforms serving as the main approach. As the complex developed, the space between the platforms was filled to form the Great Platform, the earliest version of which measured . The main pyramid B1-1 was then built upon the Great Platform, behind the western platform and covering the original central temple. The Great Platform was remodelled at least three times before it reached its final dimensions.