Smarties candy was originally made with machines that were built to make gunpowder pellets for ammunition during World War I.

The watch made its migration from the pocket to the wrist during World War I, when soldiers were obligated to attach them to their arms for coordinated attacks, instead of fumbling in their pockets. Before then, the "bracelet watch" had mostly been regarded as a joke and "silly fad."

In World War I, California’s schoolchildren were enlisted in a war on squirrels with one-sided casualties exceeding 100,000 ground squirrels.

Humphrey Bogart was a veteran of World War I, serving in the U.S. Navy aboard the USS Leviathan. Too old to reenlist in the Navy during World War II, he volunteered for the Coast Guard Temporary Reserve.

In World War I, 2 damaged Destroyers, the Nubian and the Zulu, were joined together to create the Zubian.

The 1919 Tour de France featured the lowest number of participants finishing in the race's history, due to the damage caused to French roads during World War I.

Henry Gunther was an American soldier who charged a German machine gun nest trying to regain his rank after being demoted. He was reluctantly killed by them at 10:59 am on November 11th, 1918. One minute before the Armistice took effect. Making him the last soldier killed in World War I.

Veterans Day occurs on November 11 every year in the United States in honor of the “eleventh hour of the eleventh day of the eleventh month" of 1918 that signaled the end of World War I, known as Armistice Day.

During World War I, the German government carried out a census of Jews to prove that German Jews weren't pulling their weight in the war effort. What they found out instead was that Jews were overrepresented on the front lines.

Australians developed Vegemite because they couldn't wait for Marmite supplies to resume after World War I.

During World War I, Germany attempted to preclusively purchase every hydraulic press in the US for the next two years to limit artillery shell production.

Mercy dogs were trained during World War I to comfort mortally wounded soldiers as they died in no man's land.

When Germany invaded Belgium in World War I, King Albert I took personal command of the Belgian Army. He led his army for 4 years, fighting alongside his troops, while his wife, Queen Elisabeth, worked as a nurse at the front. His 12 year-old son, the Crown Prince, also fought in the ranks.

Theodore Roosevelt's youngest son Quentin Roosevelt I was a pilot in World War I and was killed in France during combat. He is the only child of a US President to die in combat.

Mustard gas, which was used heavily during World War I, is not just a skin irritant but damages DNA by corrupting molecules in the strand. If the victim survives, the DNA damage can lead to the development of cancer.

Full-length audiobooks were originally introduced in the 1930s for people with visual disabilities, such as war-blinded World War I veterans and civilians who couldn't read braille. The average novel fit on 10 gramophone records.

The most skilled sniper in all of World War I was a Canadian Indigenous man, Francis Pegahmagabow. He had 378 confirmed kills, captured over 300 enemy soldiers, and spent his post-war life fighting for Indigenous rights. He remains the most decorated Indigenous soldier in Canadian history.

World War I boosted the modern bra market when the U.S. War Industries Board asked American women in 1917 to stop buying corsets because corset frames were mostly made of metal, which was needed for ammunition and other military supplies.

McDonalds founder Ray Kroc and Walt Disney both served as ambulance drivers in the same unit in World War I, and both had lied about their age to enlist.

Archduke Franz Ferdinand, the heir to the Austro-Hungarian Empire, repeatedly warned Vienna's hardline Chief of Staff that continued harsh oppression of the Serbians would eventually draw Austria into a war with Russia and spell the doom of both empires. Neither empire survived World War I.

In 1932, a group of World War I veterans gathered in Washington, DC to demand early payment of their service bonuses. President Hoover called in the Army to disperse the protestors. With a force of 500 infantrymen, 500 cavalry, and 6 tanks, the Army succeeded, and two veterans were killed.

People started wearing pajamas, originally spelled “pyjamas,” instead of nightgowns so they’d be prepared to run outside in public during World War I air raids in England.

The beginnings of the modern era of cancer chemotherapy can be traced directly to the German introduction of chemical warfare during World War I.

The 369th Infantry Regiment (better known as the Harlem Hellfighters) served on the front lines for 191 days during World War I, longer than any other American unit. In that time they never gave up any ground they captured.