Answer:
Mississippi River
Step-by-step explanation:
Between April 25th and May 1st 1862, American Civil war broke out which made General Butler and Admiral Farragut to capture New Orleans, thus making Natchez to surrender the control of the southern part of Mississippi River to the North.
The Union was able to capture the entire city unopposed after conquering the Fort Jackson and St. Phillips along the way, thus, this helps to reduce the level of destruction in the city, and most especially the Southern part of New Orlean. It is a major turning point in history of America as it involves the capture of the largest Confederate city.