On this day: August 20
POSTED: 12:46 AM PDT Aug 19, 2012
UPDATED: 11:00 PM PDT Aug 19, 2012
Charles Darwin publishes his theory of evolution, the NFL is founded, Lou Gehrig belts his 23rd career grand slam and NASA heads for Mars, all on this day.
NASA
1975: NASA launches the Viking 1 planetary probe toward Mars. It becomes the first spacecraft to successfully land on Mars and perform its mission, and held the record for the longest Mars surface mission of six years and 116 days until that record was broken by the Opportunity Rover on May 19, 2010.
