I live in a place where the most terrible battle occured during WWI (bataille de la Somme, even worst than Verdun). And there are still cruel marks of that dreadfull conflict.
Here's an example :
There is a small stream not far from where I live where I enjoy fly fishing for barbels & chubs (unfortunately no trout in there).
The surroundings are quite nice, like pictured bellow :
I was wading confidently within, until I noticed that stuff in the shallow water :
At first, I tought it was a bottle (though a bit bigger than a bottle of wine !!), but actually that was an old WWI bomb in place for more than 90 years !!
An other angler from the village told me they were quite common, and that he has even hooked an ammunition box !!
Don't need to say that I do not put any foot back in water since that discovery !!