Powerpoint mystery tour

http://www.pitt.edu/%7Esuper1/lecture/lec53991/004.htm

NASA Adds to Evidence of Mysterious Ancient Earthworks - The New York Times

So what are we to think now?

http://www.nytimes.com/2015/11/03/science/nasa-adds-to-evidence-of-mysterious-ancient-earthworks.html?action=click&contentCollection=Sunday%20Book%20Review&module=MostPopularFB&version=Full®ion=Marginalia&src=me&pgtype=article