South Carolina Gov. Nikki Haley, after the massacre of nine African-Americans at a historic black church in Charleston, has called for the removal of the rebel Confederate battle flag that stands outside South Carolina's Statehouse. Here's a brief explanation of the Confederate battle flag, a historic but deeply divisive symbol that remains ever-present in the American South. During the American Civil War (1861-1865), the secessionist, pro-slavery South's military flew several styles of Confederate battle flags — what most Americans think of as the Confederate flag. Parts of its design were incorporated into the state flags of South Carolina, Mississippi and Georgia — against the wishes of African-American civil rights groups who viewed it as a symbol of a brutally oppressive past.