Place the following events of the American Civil War in chronological order:
1️⃣ Attack on Fort Sumter (1861)
2️⃣ First Battle of Bull Run (1861)
3️⃣ Battle of Antietam (1862)
4️⃣ Battle of Gettysburg (1863)
5️⃣ Sherman's March to the Sea (1864)
6️⃣ Surrender at Appomattox (1865)