On this day: July 1

Published On: Jun 28 2013 03:06:05 PM CDT   Updated On: Jul 01 2014 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 - SOS
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1908: SOS goes into effect as the new Morse code international distress signal, replacing CQD. It would be used for the first time on June 10, 1909, with the Cunard liner RMS Slavonia transmitting the signal after it wrecked off the Azores.

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