In December 1977, President Jimmy Carter planned a trip to Poland, a country whose masses were, at the time, still fiercely huddled behind the Iron Curtain.

What Should Have Happened: Your average, boring-yet-passively-hostile Cold War-era visit. Carter would fly in, say a few carefully chosen words implying that maybe Poland should pay more attention to human rights, which the Poles would then slyly dismiss. Then everybody would go have a big dinner and a few shots of vodka before hitting their heavily bugged hotel rooms. No big deal.

What Happened Instead: A diplomatic snafu famous for being simultaneously politically offensive and hilarious.

The problem stemmed from Carter's Polish translator, Steven Seymour, a freelance linguist who was hired by the State Department for $150 a day. Although an accomplished and respected translator of written Polish, Seymour turned out to be less-than-apt with the spoken word. During his speech, Carter said he'd come to learn about the Polish people's desires for the future—meaning their political and economic desires.

During the translation, however, Seymour used a word that suggested the president was instead interested in the Poles' carnal lusts.

And for a second round of humiliation, when Carter later mentioned leaving for his journey back to the United States, Seymour translated it to mean Carter had abandoned America forever. Having thoroughly confused the Poles (and creeping them out in the process), Seymour further sullied his translation with Russian words—a big no-no in a country with a long history of anti-Russian cultural antagonism. Not surprisingly, he was soon replaced.

---This summer, mental_floss is re-running parts of "The 20 Greatest Mistaikes in History," Maggie Koerth-Baker's cover story from March-April 2007. To order the back issue, click here. To see other installments in this series, click here.