Significant complex civilizations, writing developed on a similar time scale. But once you have the European colonization, some people say it was intentional. It was probably a combination of intentional and just diseases that were unfamiliar to the people here. Within 150 years, that 50 to 100 million population, so now we're talking about roughly by 1650, so you move a little bit future forward in time, the population had gone to roughly six million people. Some people refer to it a genocide. Some people would say it's a combination of an intentional extermination of people plus just inadvertent disease. Whatever it is, this was the significant decline of a complex and diverse set of populations.