What Was the Battle of Gettysburg?

Which of these facts are true?
The battle went on for three days
About fifty thousand soldiers died
Generals who had been good friends fought against one another

"Four score and seven years ago…" begins Abraham Lincoln’s beautiful speech commemorating the three-day battle that turned the tide of the Civil War. The South had been winning up to this point. So how did Union troops stop General Robert E. Lee’s invasion of the North? With black-and-illustrations throughout and sixteen pages of photos, this turning point in history is brought vividly to life.