In 1893 Hershey visited the Chicago World's Fair, where he saw an exhibit of German chocolate-making equipment.

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It later makes a splash at the 1893 Chicago World's Fair.

CNN: Cleaning through the ages

The story's timeline runs from the early '20s to 1934, ending at the close of the World's Fair in Chicago.

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In 1893 Chicago held a huge fair, the World's Columbian Exposition, ostensibly to celebrate the 400th anniversary of Columbus's arrival in the Americas but in reality to bind together the city's squabbling immigrants and fractious social groups with a bit of cultural adhesive.

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