Pennsylvania became the second state to ratify the US constitution.
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A giant ball of fire was seen arching across the sky from Michigan to Pennsylvania.
A nuclear disaster occurred at Three Mile Island in Pennsylvania, US.
American driller Edwin Laurentine Drake successfully drilled the first oil well in Pennsylvania, US.
During the American Revolution, Lancaster in Pennsylvania became the capital of the United States for just one day.
The first newspaper from a vending machine was bought in Columbia, Pennsylvania.
