The main archeological site is located on a large hill called Guiengola, Gola, Gui’ngola or Guien-Gola. It and a nearby volcanic cone were fortified with walls, trenches and towers on the slopes. On the summit, terraces, bases, pyramids and temples were constructed with slabs of stone covered in stucco. The fortress city also had pens of deer and wild boar as well as artificial ponds with fish to act as food reserves. The area is filled with small ravines, which makes access more difficult. The fortifications served well in the 1490s, when the Aztecs laid siege to the city, but were unable to definitely conquer it after seven months.