As Teotihuacn declined around 700 AD Xochicalco became the dominant political and economic center for the next 200 years. It sit on a hilltop and covers nearly 20 square kilometers. Excavation has been going on only in the last 20 years. As with other ancient Mexican cities, the ball game "pelota" was very important in the culture and two ball courts have been unearthed. The most impressive monument is the Pyramid of the Feathered Serpent with its eight carvings of the serpent god Quetzalcoatl. We also enjoyed the Observatory, a tunnel deep into the rock with a shaft hewn to the sky above. In mid-May and late-July a ray of sunlight fell through the shaft to the floor below, a sort of calibration to their calendar.
