1. American Civil War
2. World War I

Thomas "Stonewall" Jackson is one of the most famous Confederate generals of the Civil War. He was accidentally shot by his own men and died (from issues stemming from pneumonia) a few days later.

1. American Civil War
2. World War I

It was Abe Lincoln, of course, who insisted that the Union must be preserved at all costs. He ordered his armies to bring the Confederacy back into the fold of the Republic before it was too late.

1. American Civil War
2. World War I

In World War I, armies were equipped with powerful new weapons but still clung to outdated battlefield tactics. To stem the tide of major casualties, both sides dug deep trenches and waited out the enemy in battles of attrition.

1. American Civil War
2. World War I

On July 1, 1916, British and French troops started a large offensive against the Germans. More than 1 million men were killed or wounded during the Battle of the Somme, a fact that ranks it as one of the bloodiest battles in human history.

1. American Civil War
2. World War I

On June 28, 1914, an angry Serbian assassinated Archduke Franz Ferdinand of Austria. Ferdinand's death caused an avalanche of political upheaval that resulted in World War I.

1. American Civil War
2. World War I

On April 14, 1865, a Southern diehard named John Wilkes Booth shot and killed President Lincoln at a local theater. Doctors tried in vain to save Lincoln's life, but he died and less than a month later, the war officially ended.

1. American Civil War
2. World War I

On June 28, 1919, the Treaty of Versailles effectively ended World War I. But its terms were humiliating for Germany, and even back then, people knew that another big war was on the horizon.

1. American Civil War
2. World War I

The Civil War ended in 1865, and what do you do after you've blasted your country to smithereens? You rebuild. But during Reconstruction, Americans weren't just rebuilding, they were retooling their values as a whole to heal the psychological wounds of the war.

1. American Civil War
2. World War I

In the early 1900s, airplanes were still a new invention. But brave pilots took the rickety aircraft into the heavens, mostly to spy on the enemy.

1. American Civil War
2. World War I

The Battle of Gettysburg was fought in Pennsylvania in early July 1863. Nearly 200,000 men clashed at the battle, which is frequently called a major turning point in the Civil War.

1. American Civil War
2. World War I

World War I is often called The Great War, and it was meant to be the war to end all wars. As we all know, it wasn't.

1. American Civil War
2. World War I

Early grenades, like the Ketchum grenade, were used in the Civil War. These grenades had iron balls filled with explosives and fins made of cardboard that were meant to stabilize the weapon's trajectory.

1. American Civil War
2. World War I

The Battle of Verdun was the biggest and longest battle between French and German armies in World War I. Hundreds of thousands of troops died during the nine-month slog.

1. American Civil War
2. World War I

Southern states wanted more power to do as they pleased, and of course, the issue of slavery was a major point of conflict. The North had no choice but to put down the rebellion with force.

1. American Civil War
2. World War I

Gen. Lee was the most famous Confederate general of the Civil War. He survived the war and then eagerly helped President Andrew Johnson's Reconstruction efforts.

1. American Civil War
2. World War I

Fort Sumter was one of the few Union strongholds in the South once hostilities commenced. It was an obvious target, and that's where the Confederates started the war. After a battle that lasted more than 30 hours, Union troops were forced to surrender.

1. American Civil War
2. World War I

There had been some minor confrontations between the North and South before Bull Run. But on July 21, 1861, both sides really went after each other, marking the first major battle of the Civil War. The South won, sparking panic amongst some Northerners.

1. American Civil War
2. World War I

The Civil War erupted when Southern states tried to secede from the Union. The War Between the States was a conflict between states in the South and those in the North.

1. American Civil War
2. World War I

The Civil War saw the first machine guns deployed in battle. The Gatling gun, for example, was a machine gun on wheels, and it could fire about 200 rounds per minute, far faster than any other weapon in the war.

1. American Civil War
2. World War I

The Civil War is still by far the bloodiest conflict in American history, with 620,000 or so total deaths. But more than eight million soldiers died in World War I.

1. American Civil War
2. World War I

John "Black Jack" Pershing was one of America's greatest World War I generals. He was the head honcho of the American Expeditionary Forces sent to help beat back the Germans.

1. American Civil War
2. World War I

Enemy troops hunkered down in deep trenches? No problem! Launch some chemical weapons like mustard gas and watch them scream and then die agonizing deaths. Yes, World War I was the pits.

1. American Civil War
2. World War I

With the North and South combined, about three million men fought in the Civil War. By the time the South surrendered, more than 620,000 (both sides combined) would die.

1. American Civil War
2. World War I

After the Civil War, legislators changed the Constitution to free slaves and to add a phrase that everyone should be given "equal protection under the law." It's one of America's dearest ideals.

1. American Civil War
2. World War I

In 1862, two metal-clad ships, the Monitor and the Merrimack, dueled off of the shores of Virginia. The battle ended indecisively, but it sparked navies around the world to do away with wooden ships in favor of those made from metal.

1. American Civil War
2. World War I

There's no contest here. While Civil War battles were typically fought with troops numbering in the thousands, World War I battles often featured hundreds of thousands or even millions of fighting men.

1. American Civil War
2. World War I

Millions of soldiers suffered terrible injuries during the World War I. Fortunately, advances in medicine (such as plastic surgery) helped doctors put some of those scarred troops back together again.

1. American Civil War
2. World War I

"Going over the top" meant that you'd been ordered to climb out of your trench and charge towards enemy lines. For World War I soldiers, going over the top was frequently a death sentence.

1. American Civil War
2. World War I

With millions of men spraying their blood all over the battlefields of Europe, doctors needed a way to keep men alive. Thus, blood banks. Thanks to donated blood kept on ice, blood banks could keep their vital fluids fresh for around a month.

1. American Civil War
2. World War I

World War I, with its liberal use of chemical weapons, is sometimes called "The Chemists' War." The effectiveness of chemical weapons got mixed reviews, but whether or not they worked, they created terror in the trenches.