are open to the public, which have been made into well-lit, arched passages. Visitors enter on the north side, through the center of the pyramid and exit on the south side. There are few signs explaining the structures within, but in one section allows a view of main staircases of one of the pyramids, whose nine floors have been excavated from bottom to top. There are also two famous murals. One is called "Chapulines," which consists of images of grasshoppers with a black skull in the middle. And the other is the "Bebedores," which depicts various figures drinking out of vessels most commonly used for pulque. Around the pyramid are a number of other structures and patios, which form a massive complex. The Patio of the Altars was the main access to the pyramid and is named for the various altars that surround a main courtyard. Initial excavations eventually indicated that the main access to the pyramid was on the west side, which latter excavations confirmed. Both also showed that there usually were minor accesses on the northeast and southwest corners. Building A or La Conejera Building A is the earliest version of the pyramid also called "La Conejera". This structure was discovered in the 1950s, near the end of the first round of excavations. It is a pre-Teotihuacan structure, relatively simple with an adobe core. However, it was not found directly under the other layers of the Pyramid, but rather under a structure known as the Edificio Rojo (Red Building) in the northeast corner. This makes the oldest pyramid of the site "off-center" in relation to the later pyramids. It was built with an adobe core with a base of about ten meters square. It has a wall in talud topped with a 57 cm cornice. Over this, a two-story chamber faced south. One side of La Conejera, eight rounded steps made of earth with a stone core lead to the west side of the structure, into a hallway. This bears some resemblance to the rounded pyramid of Cuicuilco. From the ceramics found with it, the structure has been dated to about 200 BC, contemporary with sites such as Zacatenco and El Arbolillo in the Valley of Mexico. La Conejera's base, cornice and chamber were all painted. Black paint remains on the base. The cornice on the northwest corner had white squares painted over a black background. Investigators have