Sherman's atlanta campaign was made up of two primary goals:
1. it would take away southern pride and...
2. the union needed a major victory.
Sherman was the general at this time and he was responsible for his march to the sea. Durong hos march tp the sea, everyone thinks that there was total destruction but this isn't true. Only about 30-40% of the actual city was either burnt down or destroyed. that still left a great amount of land left. Also before sherman's march, sherman and the mayor would be consistently sending letters to each other and in one of these letters, sherman asks to evacuate the city before he marches in a mean but nice way.
http://upload.wikimedia.org/wikipedia/commons/thumb/1/19/William-Tecumseh-Sherman.jpg/472px-William-Tecumseh-Sherman.jpg