On this day: July 1

Published On: Jun 28 2013 03:06:05 PM CDT   Updated On: Jul 01 2016 01:00:00 AM CDT

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.

OTD July 1 - ZIP codes
28 / 59
United States Post Office Department

1963: ZIP codes are introduced for United States mail. Simultaneously with the introduction of the ZIP code, two-letter state abbreviations were also introduced.

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