A widow, four presidents, and the letter that finally worked: how Sarah Josepha Hale gave America a national Thanksgiving.

Four days before the bloodiest day in American history, a corporal from Indiana handed his general the enemy's plan.

Seventy-four McKinsey Summer Associates walked Gettysburg with Heroes' Path. The minute made Chamberlain famous. The two years made the minute.

What actually happened on June 19, 1865, two and a half years after emancipation, and why almost no one knows about it.

At Appomattox, Grant fed his enemy and let them take their horses home to plant. Dignity is how you make victory stick.

Harriet Tubman didn't stop at her own freedom. She kept going back. Courage, she showed, is repetition on the return trip.

Meade had command for three days before Gettysburg. John contrasts his adaptive approach with Lee's fixed plan and what it means for leaders.

Columbus, Mississippi. Waterloo, New York. Charleston, South Carolina. John traces the many origins of Memorial Day.

Ordered to hold at any cost at Gettysburg, the 16th Maine tore up its flag rather than surrender it. John on its colonel, Charles Tilden.

Brady at the McPherson farm, dead horses at the Trostle barn, a staged sharpshooter at Devil's Den. John pairs Gettysburg's battle photos with the same views today.

In 1938, Union and Confederate veterans met again at Gettysburg. Some children who watched are still alive. We're two handshakes from the battle.

The 11th Pennsylvania's bull terrier was found guarding their dead on Oak Ridge after Gettysburg. Her bronze likeness still lies there.

In April 1862, Union raiders stole the locomotive General and ran it north toward Chattanooga. Six of them became the first Medal of Honor recipients.

Oliver Wendell Holmes Jr. was wounded at Ball's Bluff, Antietam, and Chancellorsville, then served on the Supreme Court until he was 90.

On the third day at Gettysburg, Lee sent about 13,000 men across open ground at the Union center. Hour by hour, John walks through Pickett's Charge.

No photograph of him survives. An Irish immigrant from Chicago captured a Confederate flag at Malvern in 1864 and earned the Medal of Honor.

Exhausted and under fire at Monocacy, Corporal Alexander Scott picked up his regiment's fallen national flag and carried both colors off the field.