Civil War’s first battle, 150 years later

>>> finally tonight, the 150th anniversary of the start of the civil war . the great southern historian shel shelby foote always said "you can't understand the united states unless you understand the civil war ." today they gathered where it started to look back upon what it started, and nbc's ron mott was there in fort sumter , north carolina .

>> reporter: a crackling predawn fire for confederate re-enactors ready for battle while across charles-to-be harbor just after 4:30 a single beam of light fired into the night sky became two, a stark symbol of a nation divided 150 years ago today. on this the cess qi centennial of the assault on fort sumter , which started america's bloody four-year civil war , wreaths for more than 600,000 people who lost their lives in their years. recognition that such sacrifice proved necessary to form a more perfect union. today's events were cast not as a celebration but a commemoration.

>> this obviously was the opening shots of what took the united states of america into a terrible civil war . i think in order for us to understand our own people, our own history, we have to understand what that civil war was about.

>> reporter: slavery of course was at the heart of the fight between north and south , and though the confederates quickly routed union forces here on fort sumter the union ultimately won the war, forever changing the course of american history . president lincoln freed the slaves before war's end, beginning a new kind of struggle for african-americans. what one historian calls a work in progress .

>> we must always remember that there's great potential in this country, its institutions, in the constitution to further the interests of civil rights and equality and justice. that's the beauty of america.

>> reporter: a beauty born of painful, self-inflicted wounds ever healing and a flag still flying united. ron mott, nbc news, fort sumter , south carolina .