At the time the first Europeans came to this country, the Native Americans of the Southwest had developed (among many other things) cities of multiple stories, amazing knowledge of astronomical events, and systems of roads that served purposes which we still have not deciphered.
All of these things were accomplished without the benefit of one of the simplest yet most powerful tools ever invented. The Europeans had long enjoyed this invention, and brought it with them to the Americas. Each of us uses this ?tool? several times a day. If it had been discovered by the Native Americans it is impossible to imagine how different our history might have been.
What tool did they lack?
All of these things were accomplished without the benefit of one of the simplest yet most powerful tools ever invented. The Europeans had long enjoyed this invention, and brought it with them to the Americas. Each of us uses this ?tool? several times a day. If it had been discovered by the Native Americans it is impossible to imagine how different our history might have been.
What tool did they lack?