This month marks the 150th anniversary of the beginning of the U.S. Civil War - a conflict that nearly tore the United States apart. Eleven southern states seceded from the Union and formed the Confederate States of America, vowing to maintain their economic system based on agriculture and slavery.
On April 12, 1861, Confederate soldiers fired on Union troops at Fort Sumter in South Carolina. It was the first act of open aggression by the South against the North. After four years of bloody battles, the Confederates surrendered.
Today, the war between the states still resonates with Americans, and in some ways, the nation is still healing from that division.
Well over a half million Americans died during the Civil War, the equivalent of losing 2 percent of the population. "You can imagine the impact that this would have on whole communities throughout the country," says Ray Brown, chief of interpretation for Manassas National Battlefield Park, site of one of the war?s first battles.
Brown believes that loss is responsible for "passions that have been passed on from generation to generation even at the remove of 150 years."
On a recent visit to Manassas, there is little evidence of that passion, but there is a desire to connect to the past. Park superintendent Ed Clark says the battlefield is a good place to do that.
"You can actually stand out here on the fields, see what they saw. But I think there is also an emotional connection that can be made on battlefields. This is a place where Americans fought. This is a place where Americans died."
The park gets about 600,000 visitors a year. People like Marianne Lee, who came with her children and their friends.
"I think it is important to look back at this particular war, because it is what made our union. We separated and yet managed to come back together."
Yale historian David Blight, one of the leading experts on the Civil War, says the United States reunited after the war "by finding the mutuality of sacrifice between the two sides."
By the 50th anniversary soldiers who fought on both sides were getting together for reunions. In 1913, some 50,000 veterans assembled in Gettysburg, the site of the war?s bloodiest battle.
"What we did in this country is we suppressed having to talk about what caused that war or what its results or legacies were, focusing largely on honoring the soldier," says Blight.
Americans continued to ignore the issues 50 years later, during the centennial of the Civil War, according to Kevin Levin. A history teacher in Charlottesville, Virginia, Levin also maintains the popular blog, Civil War Memory.
"The dominant interpretation of the early 1960s would have been focused on the bravery of Union and Confederate soldiers, the theme of reconciliation. Americans were more interested in remembering a war that united Americans rather than divided Americans."
In the last few years, there has been renewed scholarship on the Civil War by Blight and other historians.
He says that we shouldn?t forget the military history. "But this time, we need to put the story of emancipation at the center of this narrative, because what really transformed the United States, were not those battles. What really transformed the United States was the process by which 4 million slaves were freed that necessitated a recrafting of our Constituion."
Three new amendments
Following the War, three amendments were added to the Constitution. The 13th amendment abolished slavery forever. The 14th granted citizenship to anyone born in the United States and guaranteed equal protection to all citizens. And the 15th amendment guaranteed all citizens the right to vote.
Blight says the Civil War launched "a revolution in civil and political rights." But it did not last. It would take the Civil Rights movement, a full century later, to force the government to deliver fully on those promises.
Today, with an African-American in the White House, we have come a long way, but the legacies of the war are still being debated, says Blight.
"Every time Americans debate the problem of States? rights, the relationship of federal power to state power - which we are indeed having a roiling debate again, and every time we debate, not only race relations, but the very idea of what it means to be an American, multi-racial, greatly diverse society, we are debating the direct legacies of the Civil War."
That, says blogger Levin, is one of the reasons Americans are still fascinated by the Civil War.
"Even if we don?t know much about this period, there is a hold on us, an emotional hold. I think that explains why we still have a need to talk about it, because we are still struggling with many of those issues that came out of it."
And as Americans mark the anniversary over the next four years, there will be plenty of opportunities to discuss the legacies - and lessons - of the Civil War.