I have twice raised the question: “In what country was the battle of Waterloo fought?” Waterloo is now in Belgium, but that state was created fifteen years later. Well, I finally bothered to go looking for an answer to the question . .
Waterloo was fought nine days after the end of the Congress of Vienna, during which the United Kingdom of the Netherlands, which included what we now call Belgium, was created.
The question I really had in mind was: what pre-Napoleonic state? I have half a memory of concluding, tentatively, that Waterloo was in the Bishopric of Liège.