The first slide in journalist Charles C. Mann’s March 9 lecture in Pruyne Lecture Hall was a painting entitled “The Americas before Columbus,” which featured a small band of Indians riding across the Great Plains with the Rockies in the background. “It’s rare that you find a picture where everything’s wrong,” Mann remarked. It soon became clear that he was not just referring to the literal picture on the screen, but to the entire idea of the Americas that is taught in American high schools.

Author of “1491: New Revelations of the New World before Columbus,” Mann has devoted several years of research to the topic of what exactly the pre-Colonial New World looked like. His conclusion is that most of what is taught is wrong.

The classic image of the American Indian is of a people “living in small bands,” said Mann. “Touching nothing, leaving nothing,” their appearance on the stage of history is entirely irrelevant, as they barely inhabited the Americas before they were swept aside by the European colonists.

This view, according to Mann, is completely incorrect. Not only did the majority of Indians “live in cities or areas connected to cities,” but they also “shaped their environment extensively,” mostly through the use of fire. Complex Indian societies existed everywhere, from the New England area to the Amazon Basin in Brazil.

He said scholarly “estimates are that around 40 to 60 million” people lived in the New World, before they were wiped out by diseases.

“One of the central facts of history for the last 500 years,” said Mann, was the “enormous epidemiological imbalance” between the New World and Eurasia. The latest research, according to Mann, shows that diseases such as smallpox killed up to 95 percent of the native population, completely destroying native civilizations and leaving them open to the European colonists.

“Imagine all the people that died of these diseases in Eurasia over millennia, compressed into 150 years in the Americas,” Mann said. “As much as 20 percent of people on Earth died.”

“1491” illustrates what was lost in these epidemics. Mann showed aerial photos of land in Peru where the entire landscape had been shaped into mounds and causeways by a native society that has not even been recorded in colonial accounts. At the same time, the Amazon was home to a large population who had indeed created the forest we see today. “The reason all these [useful] species are found is they were planted ... When you look at the banks of the Amazon, you’re looking at the world’s biggest orchard.”

Though careful to emphasize that the “Indians weren’t saints,” Mann’s theme was that Indians had made a massive impact on the environment, and that the “natural” environment that Europeans had come across was largely artificial.

Mann also stressed that efforts to restore the native environment might be counterproductive in that they try to restore an ecology that was never there. “We were trying to recreate the wilderness,” he said of his days planting trees in high school, “We created a disaster. Part of the reason there are these terrible fires in the [American] West is due to people like me.”

According to Mann, people have to decide how the land should look themselves. “People aren’t all bad,” Mann joked.