aka the Loreley song, originally written as an untitled poem by Heinrich Heine for his second poetry collection, Das Buch der Lieder. A composer named Friedrich Silcher then came up with an earworm of a melody for it, and it got enthusiastically sung as a folk song by Germans thereafter to this very day. Chances are that if you've ever heard a German folk song, it will be this one.

I learned it first as an art song, with credit to Heine, but I was definitely not in Germany at the time.