They brought back golds and silvers
World War I completely changed the way wars were fought.
Trench warfare, which was the norm just a century ago was seen as an nonviable strategy.
Modern machines such as tanks and airplanes made trench warfare mostly about keeping ground and resulted in stalemates.
Also, it was the first time that modern tanks, planes and machine guns were being used for first time at such a large scale, resulting in an unprecedented level of death and carnage.
Military generals soon realized that time-honored military code of conducts were now obsolete and a completely new form of strategy was now required.
By being in the north and wanting the south to rid of slaves, and to make them join the north. but the south only had huge amounts of farm land, and no way to sow, till, or harvest all that land with out a few hundred slave workers. the north seen that as unnescessary to do. the north also laid out laws that the south didnt agree with leading to the southern states declaring independancy against the north witch lead to war.
The correct answer is cameras
