Once upon a time - I've seen this story in several versions and several places, sometimes cited as fact, but I've never tracked down an original source - once upon a time, I say, the US Army wanted to use neural networks to automatically detect camouflaged enemy tanks.

This document has a citation for the story: (Skapura, David M. and Peter S. Gordon, Building Neural Networks, Addison-Wesley, 1996.) I don't know for sure if that is the end of the trail or not.