Answer: The Seige of Vicksburg
Explanation: The Seige of Vicksburg was the final major military action in the Vicksburg campaign of the American Civil War in 1863. Vicksburg was the last major Confederate stronghold on the Mississippi River; therefore, capturing it completed the second part of the Northern strategy, the Anaconda Plan. The siege was one of the longest sieges in history; it lasted for 40 days. Confederates were forced to eat rats, cats, dogs and mules to survive.