Every war picture I see I always wonder what is going through their minds at the moment it’s captured.
The Moaning Minnie is the 10-tube rocket launcher on top of the vehicle. The vehicle itself is a German Maultier (Mule). When the rocket projectiles were launched they made a distinctive sound and were known among Western forces as “Screaming Mimis” or “Moaning Minnies.”
The Russian rocket launchers mounted on trucks (such as the BM-13) and known as Katyushas or Stalin’s Organs and the American application of the idea atop Sherman tanks known as the Calliope were named for the resemblance of the multiple launch tubes to church organs or similar instruments and not for the sound they made when firing.