They all stopped liking Eachother
It depends on which war you're referring to. I feel that the answer you're looking for is the radio, though.
I believe the answer you’re looking for are (Slavs)-who are an ethnic group that is dispersed across Europe with large concentrations in eastern countries like Bulgaria and Russia.
The market revolution sparked explosive economic growth and new personal wealth, but it also created a growing lower class of property-less workers and a series of devastating depressions, called “panics.” Many Americans labored for low wages and became trapped in endless cycles of poverty.
