Is it ensure, insure, or assure?
A movement of the Union army troops of General William Tecumseh Sherman from Atlanta, Georgia, to the Georgia seacoast, with the object of destroying Confederate supplies. The march began after Sherman captured, evacuated, and burned Atlanta in the fall of 1864. His men, numbering about sixty thousand, destroyed railroads, factories, cotton gins, houses, livestock, and anything else that might be useful to the South in the war.
Note: Northerners celebrated Sherman's march with the song “Marching through Georgia.” Southerners remembered it bitterly.