Igor Markov's answer to Why does the US government spend so much on military? Jon Davis' answer to Given that China is fine without blue-water navy, why does the US need one? Being even is the Deadliest form of Warfare
Imho the most influential war in history is the Caesar Augustus' failing attempt to conquer the Germans. He sent two legions over the Limes Renano expecting to tame the german population. It didn't happened: in the Battle of Teutoburg Forest the army of 15.000 well trained roman solders was completely slayed but Germans. In a what if...
the first major battle in the American Civil War to take place on Northern soil. It was the bloodiest single-day battle in American history, with almost 23,000 casualties. After this win for the North, Lincoln announced the Emancipation Proclamation. Emancipation Proclamation.