The Spaniards marveled at the incredible sights of Tenochtitlán, but were horrified by the darker side of the culture - especially the bloody sacrifices, which took place across the rooftops of the city.

Bernal Diaz del Castillo describes a visit to an Aztec temple:

They had an exceedingly large drum there, and when they beat it the sound of it was so dismal and like, so to say, an instrument of the infernal regions, that one could hear it a distance of two leagues, and they said that the skins it was covered with were of those great snakes. In that small place there were many diabolical things to be seen, bugles, and trumpets and knives, and many hearts of Indians that they had burned in fumigating their idols, and everything was so clotted with blood, and there was so much of it, that I cursed the whole of it, and as it stank like a slaughter house we hastened to clear out of such a bad stench and worse sight.

Bernal Diaz, "The Conquest of New Spain," c.1565