may 14, 1804 - Lewis and Clark Expedition
The Lewis and Clark expedition was a social event because it was informing society on what was out there. The expedition lasted for two and a half years. Only one man died on the dangerous mission and it was from an appendicitis. When they returned, they met literal boat loads of traders heading upstream to the country that they had been exploring. They were treated like national heroes and on the trip was the first time that a black man had a vote in the history of the US.
Added to timeline:
Ellie Syth's timeline of 1800-1850