The USSR and other Warsaw pact nations invaded
<u>Machine Guns</u> because tanks and poison gas weapons had not been created yet until i think WW1
During the Neolithic revolution, people started settling in river valleys and establishing cities because they developed agriculture. It was of extreme importance for the development of human society because things like states were established and laws and people started developing basic science and things like that. Just look at how Egypt and Mesopotamia developed and how they influenced many other nations that came later.
I believe there was a race riot in Chicago in 1919. I hope this helps
