The Battle of Gettysburg
In only three days this battle killed many American soldiers (Confederate and Union) also known to be a great shift in battle for the Union. The Confederate army were driving the Union back deep into their territory. They were almost driven back to where President Lincoln was. If the Union was to let the Confederacy force Abraham into slavery, we would probably be into slavery till this day. However, Robert E. Lee, the General of the Confederate army formed an assault (also known as the "Pickett's Charge") that lost them the battle giving the Union a better advancement in the war, possibly the biggest turning point in United States History.