"...that in turn led to my explaining how german bombers dumped bombs as they fled and so our countryside had bomb craters in the local woods and unfortunately destroyed some medieval cottages and the local watermill."

One of my Brit co-workers grew up on a family farm somewhere over in the West Country. The farm adjacent had a decent-sized pond on it. His father explained that the pond originated from the crater formed by the dumping/detonation of a German aerial/parachute mine. No sound of its descent, just the deafening massively destructive blast of the thing exploding just a few yards in the air. Fortunately, no casualties resulted, but lots of earth moved and the destruction of a length of dry-stone wall, much of which was found a considerable distance away.

The concept of such a s thing is, frankly, terrifying.