I find this all very interesting. There was one piece of information that I question, however. That is the date of 1.7 million years ago being the date of a contructed bridge. I just reread AlanF's work on the dates of homosapians. According to the research he presented, simple stone cutting tools only go back 250,000 years, not 1.7 million years. (You can find his work by clicking on the research site found at the bottom of this page.)