To know Americano coffee was the style of espresso served in Italy, and the fighters found it excessively solid for their range. To speak to the American taste, some high-temp water was served close by the coffee, and the men poured the water over the coffee to make a more recognizable-tasting mug of espresso.
Presently, the story may or might be valid. During WWII, espresso would have been rare in Italy, and in the event that there was, it was surely apportioned. In any case, we do know "Espresso Americano" signifies "American espresso" in Italian. Do you need more information? What is iced Americano coffee?