Monte Alban: Building J or the "Observatory". Being an astronomer, George was facinated with this building. In fact he thinks it is one of the oddest buildings to be encountered in Meso-America. Built sometime between 100 BC and 200 AD in at least three different phases, it has astronomical alignments with the setting positions of the Southern Cross and Alpha and Beta Centauri, and the rising position of Capella. It has many characteristics which set it apart from the rest of the city. The most obvious is the orientation of the building, running at a roughly 45 degree angle east of north from the rest of the site. Also, it has a peculiar arrowhead shape. Unlike the symmetrical layout exhibited by most Meso-American structures, the Observatory is designed so that no two walls or angles have the same measurements. Along the back walls of the building are an array of stone plaques depicting different scenes and figures from Monte Alban including scenes of astronomical importance such as sighting sticks. Rather than showing a series of connected scenes, the display is somewhat haphazard, with some of them even apparently upside down. This suggests that they were not crafted with this location in mind but that they were relocated from older sites and then placed in the Observatory. This odd orientation and sizing, along with many of the carvings, are what has lead to the speculation that this building was an ancient observatory. While anthropologists have yet to find a solid reason for the hall way which leads through the building, they have found many astronomical alignments associated with the building. Using a planetarium to recreate the sky as it would have appeared in BC 250 reveals that at the time the point where the Southern Cross sets in the west was almost directly where the rear of the building points to the horizon. In addition, a sightline running perpendicular from the doorway atop the stairs runs directly over a sight tube in the stairwell of Building P which was probably used to sight Pleiades and as a zenith tube similar to the one found in Xochicalco. Another sightline running perpendicular from a door at the top of the stairs, which was placed at an angle 4 degrees off the stairs, leads through a doorway on the top of Building P and announced the annual rising of the star Capella. This took place annually on the same day the sun reached its zenith above Monte Alban and likely served to give the priests advanced notice of this event (Aveni pp.249-57). The carvings on Building J record possible conquests of neighboring cities. These carvings depict named hills (in the Zapotec writing system) with severed or upside-down heads hanging from them. There are also several tunnels, or sighting slots cut through the structure, and the structure appears to have been aligned with the star system of Capella. Building J is roped off so that it can net be climbed any longer. These pictures will show some of the "sighting tunnels" and views from the top of Building J.