Hot dogs were invented in Germany and Austria.
Staples of baseball parks and summer cookouts alike, the humble hot dog was possibly discovered in ancient Rome, when the cook of Nero, a Roman emperor, removed and stuffed the intestines of a roast pig.
But what we know for certain is that the tubular meat we're familiar with today originated in one of two European towns (both vie for the honor): Frankfurt, Germany (hence, "frankfurter"), and Vienna, Austria (the word "wiener" comes from the city's German name, Wien).
Generally, it is agreed upon that European immigrants in New York popularized the dish stateside. Most famously Nathan Handwerker, a Jewish immigrant from Poland who worked at a Coney Island frank stand when he opened his own stand — the now-iconic Nathan's Famous, in 1916.