Paris, France
Flying buttresses. We enjoyed visiting Notre Dame. Girls spotted cool features on the facade, and we managed to be reasonably quiet inside. There was a mass going on inside, so kids got some exposure to religion, check that box for parenting responsibilities. Sure it was in French , details. After all, we took them to see Godspell in English last year. After Notre Dame, we spent the day walking, eating, and playing outside.
We even got to watch a policeman...