On this day: July 1

POSTED: 4:06 PM Jun 28 2013   UPDATED: 2:00 AM Jul 01 2013
Sony Walkman cassette player

The Battle of Gettysburg begins, America's first zoo opens, the first Tour de France starts, the Sony Walkman hits the market, the PG-13 movie rating is introduced, and the Deepwater Horizon oil spill breaks an unfortunate record, all on this day.