In a wooded cemetery in Munich, a white sticker with a puzzling QR code appeared on a gravestone late last year. Then, over the next few weeks, more and more stickers mysteriously appeared, until more than 1,

Police in Munich are investigating why the stickers were put on gravestones and wooden crosses at three cemeteries in the German city.

The stickers surfaced in recent days at the the Waldfriedhof, Sendlinger Friedhof and Friedhof Solln cemeteries.