Although it was once hypothesized that these were made by giant extraterrestrial figures, scientists now say that the Indians could have made them with special techniques. However, the why's still remain. Many of the Indian groups used a numbering sequence to count objects, timekeeping and calendars, and dozens of writing systems. In the Adena villages in the Ohio Valley, the residents grew "a multifarious suite of crops," such as tobacco, barley, maygrass, and knotweed. The Adena also built huge tombs for their nobles, which included copper beads and bracelets, stone tablets and collars, textiles and awls and stone pipes (256). The "Rubber People" may have invented rubber and used it themselves. The first traces of these people go back to 1800 BC.

That brings up another interesting aspect about the book -- it is not only the number of people who lived here that is amazing, but also the length of time they were established before the settlers came. The book includes the rise and fall of empires over a 20 millennia time period. The U.S., in comparison, is just a minor bump in the time line.

In many situations, Mann further describes information about a location and the different theories that are still not resolved in the endnotes. Although the notes to go with the copy are way in the back of the book, rather than at the end of the chapter or at the bottom of the page, they are easy to find with...

There are also appendixes giving additional in-depth material not contained in the front copy.
Mann's central theme that runs throughout the book as well as more in the later chapters is the Indian's understanding of the environment. He looks seriously at the conflict between the environmentalists and developers over time and now. It is a continuous controversy of humankind civilization vs. conservation. Unfortunately, his answer is somewhere in the middle and not very well expressed.

It is unfortunate that another main theme is the illness and decimation the Indian civilizations. The first smallpox epidemic in 1533 and subsequent ones killed "scores and hundreds," recalled one eyewitness to one of the outbreaks: "Villages were depopulated. Corpses were scattered over the fields or piled up the houses or huts...The fields were uncultivated; the herds were untended..." (87)

Mann's book and informative yet relaxed style of writing makes you really feel about these Indians and disappointed that they had to die out as they did -- that they had to die out at all. The next best thing is reading about them and Mann offers that opportunity.

References

Mann, Charles. 1491. New York: Albert Knopf, 2005.