A 10,5 cm schwere Kanone 18 has suffered an internal explosion, completely destroying the field gun. “But isn’t a gun supposed to be able to take an explosion? After all, the charge firing the grenade is pretty strong”, people might object. Yes, but there can be several reasons for a barrel getting destroyed like that. One is intentional destruction, “spiking the gun” in order to deny it to the enemy in case you have to abandon your position, but haven’t got the time or means to take the gun with you. There were even special charges for that (Sprengpatrone Z), made for different calibers. Another reason could be a worn barrel, but there were shot counters that were used to keep track on how many rounds had been fired so the barrel could be replaced in time. Still, a production flaw, like a miniscule crack or small impurity, could lead to a catastrophic failure. A third reason could be the grenade going off or getting stuck right after the charge has been ignited. While the gun breech can take the force of a blast, the barrel itself isn’t thick enough to withstand the force of an explosion. It could be really messy for the gun crew; if they were lucky, they got away with just the shock, but the blast and shrapnel could just as well maim or kill them. There’s no hint of the fate of the crew manning the gun in the photo. For their sake, I hope they survived to tell the tale in their letters home.