Today is September 13, but the bad luck tag on Fridays known as  paraskevidekatriaphobia ,  is not associated with other days of the week.  109 days remain until the end of the year.  Back in history on  September 13 : 1501:  Michelangelo began work on his statue of David.  I visited David when I once spent some time in Florence on a bioreactor exchange program Is a 17-foot tall statue of the future king who faced Goliath. He is left-handed. Said to be worth $200 million. The city of Florence and national government of Italy are fighting over who owns him. There are numerous replicas, two in Florence. The circumcision was minimal.  Sometimes a fig leaf has been used to avoid censorship. Supposedly, those four presidential four faces on Mount Rushmore today would cost  $11 billion . 1609:  Henry Hudson reaches the river that would later be named after him. 1788:  The Philadelphia Convention sets the date for the first presidential el...