>all of those Mayan ruins
They practiced human sacrifice. Like the Aztecs, many were wiped off the face of the Earth when the Catholic Spanish discovered this. The media calls this "genocide" but most would call it justice.
Human sacrifice happened in North America too. They stopped when they heard the Spanish were basically, wiping out Indians who did this. At least this is what I believe happened (much is not in the History books because they don't want it to be)