The Mesoamerican civilization of the Maya developed highly advanced cities, writing, calendars, and mathematical and astronomical systems. They built grand temple-pyramids and palaces in cities like Tikal, Palenque, and Chichen Itza between 250-900 CE. The Maya had a complex pantheon of gods and engaged in human sacrifice. Their advanced calendars and hieroglyphic writing declined after severe droughts in the 9th century led to warfare and abandonment of the major cities.