The Civil War began 150 years ago this week, when Confederate forces fired on Fort Sumter. The four years of bitter conflict that followed still echo in America today. “At every point in the history of this country, we feel like we're on the verge of Civil War,” historian Adam Goodheart tells Kurt Andersen. America’s leading artists pioneered new ways of depicting battle. And for some, the battles still haven’t ended: Civil War culture thrives among the re-enactors, where a gun and a uniform are a ticket to a time machine.