On July 1, 1963, the U.S. Post Office Department introduced the ZIP code program to get a handle on the heaping surplus of mail. Today, those five digits represent much more for American society. Back ...

Back in the 1960s, there was a heaping surplus of mail in the U.S. Post offices were struggling to keep up with deliveries. According to the Smithsonian's National Postal Museum, mail volume reached ...