VIENNA, AUSTRIA- Police are puzzled by an exploding hand grenade inside a wood stove since the woman who owns it says she only put wood inside. Police say the World War II grenade apparently landed on a tree during fighting but did not go off. It was then enveloped by the tree growing around it to the point that it was invisible when the tree was chopped down for firewood. The wood was sold to a supermarket where the unidentified woman bought it. The explosion was in the town of Gmuden and shattered the stove's glass panel. The woman wasn't hurt since the sturdy wrought-iron stove contained the blast.