Fort Sumter - A small group of US soldiers were led by Major Robert Anderson to Fort Sumter and they fired the first shots of the Civil War were fired April 12th, 1861. These first shots started the first war.
Battle of Antietam - The Confederacy and Union ran into each other at Antietam Creek, the battle was on September 17, 1862. The Union won freeing all slaves on September 22, 1862 when the Emancipation Proclamation was signed.
All slaves are free!
Battle of Vicksburg - The battle lasted from May 18 to July 4, 1863. The Union won gaining control of the Mississippi River, it had economic importance as a shipping port. When it fell it split the Confederacy into two unconnected parts.
Battle of Gettysburg - Battled from July 1st to July 3rd, 1863 in the deadliest battle in the war with a ton of casualties. The Union crushed the Confederacy in this battle, President Lincoln gave his Gettysburg address on November 22nd the same year.