The Siege of Vicksburg was important to the Union troops because they were able to take control of the Mississippi River. This allowed the Union troops to cut the Confederacy in half and allowed the Union to cut of supplies/resources to Confederate states.
The Battle of Gettysburg was an important Union win because this was the last time in the Civil War that the Confederate troops truly invaded the North. After this battle they did not invade any state north of Pennsylvania.
The most significant changes were the Catholic Church, Commerce, and finally Intellectual Changes. These three were my top choices as how they had the most effect on Europe.
The Congress of Vienna was held in order for the powers of Europe to settle territories and boundaries after the fall of Napoleon's Empire in the early 1800's. The conservatives such as Austria and Prussia were quite dominant during the Congress. Their goal was to set some sort of legitimacy in the system that rules Europe, and to balance out power in the continent. France was quite vulnerable and unstable due to its background. However, instability of government was also the case for other European countries. The reason why the conservatives had their goals, is because the liberalism incited by the French Revolution has been consistent with manifesting that it has failed to keep a government's stability. Therefore, it was actually the conservatives who were successful during the Congress, as they were able to achieve their goal of keeping Europe peaceful for about a century.
