The temples of the Ancient Mexicans were very numerous. They were called _teocallis_,[4] or 'houses of God,' and were constructed by facing huge mounds of earth with brick and stone. They were pyramidal in shape, and built in stages which grew smaller as the summit was reached. The bases of some of these teocallis were more than one hundred feet square. The great teocalli at Mexico, for example, was three hundred and seventy-five feet long at the base, and three hundred feet in width. Its height was over eighty feet. It consisted of five stages, each communicating with the other by means of a staircase which wound around the entire edifice. In the case of some teocallis, however, the staircase led directly up the western face of the building. At the top two towers, between forty and fifty feet in height, stood perched upon a broad area. Inside these were kept the idols of the gods to whom the teocalli was sacred. Before these towers stood the stone of sacrifice, and two altars upon which the fires blazed night and day. In the city of Mexico six hundred of these fires rendered any artificial illumination at night superfluous. Through the very construction of these temples all religious services were of a public nature. In front of the great teocalli of Mexico stretched a court twelve hundred feet square, around which clustered the chapels of minor deities, and those captured from conquered peoples, as well as the dwellings and offices set apart for the attendant priests. Although it appears that the Toltecs, the forerunners of the Aztecs in Mexico, had at one period of their history been prone to human sacrifice, they had almost entirely discarded the practice at the time of their downfall. Some two hundred years before the coming of the Spaniards the Aztecs had adopted this abomination, and were in the habit of sparing the lives of immense numbers of prisoners of war solely for the purpose of offering them up to the national gods. As their empire extended, these holocausts became greater and more common. On the teocalli of Mexico the Spaniards could count one hundred and thirty-six thousand human skulls piled in a horrid pyramid.