What were the most important events of the civil war and why?

Fort Sumter April 12, 1861: The fort is best know as the site where the shots that started the American Civil War were fired.
Fort Sumter is on Charleton Harbor. Major Robert Anderson surrendered the fort and evacuated the next day.

Battle & Capture of New Orleans
April 13, 1862:
Lee's army was surrounded, weak, and exhausted. He had decided that surrender would be best because he knew it wouldn't be a good turnout. This was important to the civil war because it meant that it was finally over.

Lee Surrenders to Grant
April 9, 1865:
The Battle of Antietam,also known as Battle of Sharpsburg, was the first major battle of the American Civil War on union soil. It was important because it was the battle where Lincoln decided to issue the Emancipation Proclamation. He was waiting for a union victory so it wouldnt come across as desperate.

Battle of Monitor & Merrimack
March 8, 1862: The battle of Monitor and Merrimack, also known as battle of Hampton Roads, was most noted and arguably most important navel battle of the American Civil War, because it was the first.

Emancipation Proclamation
January 1, 1863
The Emancipation Proclamation declared all slaves free, however not all southerners would allow that. Lincoln actually had to issue it twice, the second time it was added to the 13th amendment which a year later completely freed the slaves.