The biggest war that the world had ever experienced, and in which there were by far the most deaths was the World War II. It was a war started by the Axis Powers, and it was opposed by the Allied Powers. Millions of people ended up dead, injured, or displaced because of the war, and the countries suffered lot of damage as well. The war ended with a win for the Allied Forces. Once over, the Allied Forces put restrictions and surveillance over the countries that started the war, and focused them on economic development instead of military one. The people responsible for the war were sentenced to prison. Unfortunately, after the war, the different interests of the two biggest powers, the US and the USSR, pushed the world into the Cold War period, which was a period of tension and fear of another war, lasting for half a century.
The answer is helped. Trade was foundational to the growth of cities because it helped. Guaranteed an exchange of goods and idea made reliance on other civilization possible showed military strength gave people jobs.
It was also known as the stone era, so people started with stone tools then.
The Amazon River's source is at the base of the Mismi.
I believe it's "Laffer Curve".
