What Made the Battle of Gettysburg Different from Other Battles

What made the Battle of Gettysburg different from other battles fought in the Civil War?

A) It was the longest battle fought during the Civil War.
B) More soldiers combined from both sides died there than in any other battle.
C) The Confederacy was able to control all the immediate territory around Washington, D.C.
D) It was the only battle fought on Union soil that did not include the Border States.