Photo Credit: Keith Gandy
According to an AP report (here) from December 4th, 2014 out of Vienna, Austria, a woman placed firewood in her wood-burning stove and it exploded with a grenade blast.
"Police spokeswoman Petra Datscher said Monday a World War II grenade apparently landed on a tree during fighting. It was then enveloped by wood growing around it to the point that it was invisible when the tree was chopped down for firewood and sold to the supermarket where the unidentified 22-year-old woman bought it."
"The blast Sunday in the lakeside town of Gmunden shattered the stove's glass panel, but the sturdy wrought-iron stove prevented injuries."
Unexploded ordinance is a problem for urban Europe. We have evacuated our home twice when street repairs exposed 750 lb. bombs that fell into soft mud. Bomb crews respect their volatility and blow them up in place with plastic explosives.
Fighting of yesteryear does have long lasting effects and will from time to time rear its ugly head. Be careful of things you say - it does provide quick release in the moment, but could come back with a bang, even if grass grows over the wound.