Abraham Lincoln's Emancipation Proclamation formally took effect, declaring enslaved people in Confederate territory free and reframing the Civil War as a fight against slavery.

The Metropolitan Railway opened in London, launching the world's first underground passenger railway and transforming urban transit forever.

Union General Ambrose Burnside's attempt to flank Lee's army collapsed into chaos as torrential rain turned Virginia roads into impassable mud.

Representatives of English football clubs met in London to draft the first formal rules of association football, separating it from rugby.

Confederate forces under Richard Ewell crushed Union troops at the Second Battle of Winchester, opening the way for Lee's invasion of Pennsylvania.

Confederate cavalry and infantry under Robert E. Lee cross into Pennsylvania, opening the campaign that would culminate at Gettysburg.

West Virginia became the 35th U.S. state, carved from Confederate Virginia by counties that refused to secede with the rest of the state.

Union and Confederate forces collided at Gettysburg, Pennsylvania, opening a three-day battle that would become the Civil War's bloodiest and most decisive.

Confederate forces assaulted Union lines at Little Round Top, Devil's Den, and the Peach Orchard on the second day of Gettysburg, the Civil War's turning battle.

Confederate General George Pickett's doomed charge across open farmland shattered Robert E. Lee's invasion of the North and turned the tide of the American Civil War.

Working-class New Yorkers, furious over Civil War conscription, launched days of violent rioting that killed over 100 people, many of them Black residents targeted by mobs.

Furious mobs opposed to Civil War conscription set fires and attacked Black New Yorkers, igniting four days of the deadliest riots in American history.

The 54th Massachusetts, one of the first Black regiments in the Union Army, led a doomed but electrifying assault on Fort Wagner in South Carolina.

Henry Ford, who would revolutionize industrial manufacturing with the moving assembly line, was born on a farm near Dearborn, Michigan.

Abraham Lincoln delivers a 272-word address at the dedication of a Civil War cemetery, redefining the war as a test of democracy itself.

Union forces under General Ulysses S. Grant launched the Battle of Chattanooga with an assault on Orchard Knob, beginning three days that broke the Confederate siege.

Union troops under Ulysses S. Grant stormed Missionary Ridge outside Chattanooga, breaking Confederate lines and securing Tennessee for the North.