Today I finally learned why they call post codes “ZIP codes” in the US. The United States Postal Service introduced them in 1963, ZIP is actually an acronym for “Zone Improvement Plan”, and the name alludes to the idea of mail travelling more efficiently and quickly (zipping along) when ZIP codes are used in postal addresses. (See https://en.wikipedia.org/wiki/ZIP_Code)

This incredible stamp was designed by Randall McDougall in 1973.