World War I, also known as the Great War, began in 1914 after the assassination of Archduke Franz Ferdinand of Austria. His murder catapulted into a war across Europe that lasted until 1918. During the conflict, Germany, Austria-Hungary, Bulgaria and the Ottoman Empire (the Central Powers) fought against Great Britain, France, Russia, Italy, Romania, Canada, Japan and the United States (the Allied Powers). Thanks to new military technologies and the horrors of trench warfare, World War I saw unprecedented levels of carnage and destruction. By the time the war was over and the Allied Powers claimed victory, more than 16 million people—soldiers and civilians alike—were dead.
Tensions had been brewing throughout Europe—especially in the troubled Balkan region of southeast Europe—for years before World War I actually broke out.
A number of alliances involving European powers, the Ottoman Empire, Russia and other parties had existed for years, but political instability in the Balkans (particularly Bosnia, Serbia and Herzegovina) threatened to destroy these agreements.
The spark that ignited World War I was struck in Sarajevo, Bosnia, where Archduke Franz Ferdinand—heir to the Austro-Hungarian Empire—was shot to death along with his wife, Sophie, by the Serbian nationalist Gavrilo Princip on June 28, 1914. Princip and other nationalists were struggling to end Austro-Hungarian rule over Bosnia and Herzegovina.
The assassination of Franz Ferdinand set off a rapidly escalating chain of events: Austria-Hungary, like many countries around the world, blamed the Serbian government for the attack and hoped to use the incident as justification for settling the question of Serbian nationalism once and for all.
Because mighty Russia supported Serbia, Austria-Hungary waited to declare war until its leaders received assurance from German leader Kaiser Wilhelm II that Germany would support their cause. Austro-Hungarian leaders feared that a Russian intervention would involve Russia’s ally, France, and possibly Great Britain as well.
On July 5, Kaiser Wilhelm secretly pledged his support, giving Austria-Hungary a so-called carte blanche, or “blank check” assurance of Germany’s backing in the case of war. The Dual Monarchy of Austria-Hungary then sent an ultimatum to Serbia, with such harsh terms as to make it almost impossible to accept.
World War I Alliances
World War I Begins
Convinced that Austria-Hungary was readying for war, the Serbian government ordered the Serbian army to mobilize and appealed to Russia for assistance. On July 28, Austria-Hungary declared war on Serbia, and the tenuous peace between Europe’s great powers quickly collapsed.
Within a week, Russia, Belgium, France, Great Britain and Serbia had lined up against Austria-Hungary and Germany, and World War I had begun.
According to an aggressive military strategy known as the Schlieffen Plan (named for its mastermind, German Field Marshal Alfred von Schlieffen), Germany began fighting World War I on two fronts, invading France through neutral Belgium in the west and confronting Russia in the east.
On August 4, 1914, German troops crossed the border into Belgium. In the first battle of World War I, the Germans assaulted the heavily fortified city of Liege, using the most powerful weapons in their arsenal—enormous siege cannons—to capture the city by August 15. The Germans left death and destruction in their wake as they advanced through Belgium toward France, shooting civilians and executing a Belgian priest they had accused of inciting civilian resistance.
Life in a Trench
First Battle of the Marne
In the First Battle of the Marne, fought from September 6-9, 1914, French and British forces confronted the invading Germany army, which had by then penetrated deep into northeastern France, within 30 miles of Paris. The Allied troops checked the German advance and mounted a successful counterattack, driving the Germans back to north of the Aisne River.
The defeat meant the end of German plans for a quick victory in France. Both sides dug into trenches, and the Western Front was the setting for a hellish war of attrition that would last more than three years.
Particularly long and costly battles in this campaign were fought at Verdun (February-December 1916) and the Battle of the Somme (July-November 1916). German and French troops suffered close to a million casualties in the Battle of Verdun alone.
The bloodshed on the battlefields of the Western Front, and the difficulties its soldiers had for years after the fighting had ended, inspired such works of art as “All Quiet on the Western Front” by Erich Maria Remarque and “In Flanders Fields”by Canadian doctor Lieutenant-Colonel John McCrae. In the latter poem, McCrae writes from the perspective of the fallen soldiers:
Published in 1915, the poem inspired the use of the poppy as a symbol of remembrance.
Visual artists like Otto Dix of Germany and British painters Wyndham Lewis, Paul Nash and David Bomberg used their firsthand experience as soldiers in World War I to create their art, capturing the anguish of trench warfare and exploring the themes of technology, violence and landscapes decimated by war.
On the Eastern Front of World War I, Russian forces invaded the German-held regions of East Prussia and Poland, but were stopped short by German and Austrian forces at the Battle of Tannenberg in late August 1914.
Despite that victory, Russia’s assault had forced Germany to move two corps from the Western Front to the Eastern, contributing to the German loss in the Battle of the Marne.
Combined with the fierce Allied resistance in France, the ability of Russia’s huge war machine to mobilize relatively quickly in the east ensured a longer, more grueling conflict instead of the quick victory Germany had hoped to win under the Schlieffen Plan.
From 1914 to 1916, Russia’s army mounted several offensives on World War I’s Eastern Front, but was unable to break through German lines.
Defeat on the battlefield, combined with economic instability and the scarcity of food and other essentials, led to mounting discontent among the bulk of Russia’s population, especially the poverty-stricken workers and peasants. This increased hostility was directed toward the imperial regime of Czar Nicholas II and his unpopular German-born wife, Alexandra.
Russia’s simmering instability exploded in the Russian Revolution of 1917, spearheaded by Vladimir Lenin and the Bolsheviks, which ended czarist rule and brought a halt to Russian participation in World War I.
Russia reached an armistice with the Central Powers in early December 1917, freeing German troops to face the remaining Allies on the Western Front.
The Harlem Hellfighters
America Enters World War I
At the outbreak of fighting in 1914, the United States remained on the sidelines of World War I, adopting the policy of neutrality favored by President Woodrow Wilson while continuing to engage in commerce and shipping with European countries on both sides of the conflict.
Neutrality, however, was increasing difficult to maintain in the face of Germany’s unchecked submarine aggression against neutral ships, including those carrying passengers. In 1915, Germany declared the waters surrounding the British Isles to be a war zone, and German U-boats sunk several commercial and passenger vessels, including some U.S. ships.
Widespread protest over the sinking by U-boat of the British ocean liner Lusitania—traveling from New York to Liverpool, England with hundreds of American passengers onboard—in May 1915 helped turn the tide of American public opinion against Germany. In February 1917, Congress passed a $250 million arms appropriations bill intended to make the United States ready for war.
Germany sunk four more U.S. merchant ships the following month, and on April 2 Woodrow Wilson appeared before Congress and called for a declaration of war against Germany.
With World War I having effectively settled into a stalemate in Europe, the Allies attempted to score a victory against the Ottoman Empire, which entered the conflict on the side of the Central Powers in late 1914.
After a failed attack on the Dardanelles (the strait linking the Sea of Marmara with the Aegean Sea), Allied forces led by Britain launched a large-scale land invasion of the Gallipoli Peninsula in April 1915. The invasion also proved a dismal failure, and in January 1916 Allied forces staged a full retreat from the shores of the peninsula after suffering 250,000 casualties.
Did you know? The young Winston Churchill, then first lord of the British Admiralty, resigned his command after the failed Gallipoli campaign in 1916, accepting a commission with an infantry battalion in France.
British-led forces also combated the Ottoman Turks in Egypt and Mesopotamia, while in northern Italy, Austrian and Italian troops faced off in a series of 12 battles along the Isonzo River, located at the border between the two nations.
Battle of the Isonzo
The First Battle of the Isonzo took place in the late spring of 1915, soon after Italy’s entrance into the war on the Allied side. In the Twelfth Battle of the Isonzo, also known as the Battle of Caporetto (October 1917), German reinforcements helped Austria-Hungary win a decisive victory.
After Caporetto, Italy’s allies jumped in to offer increased assistance. British and French—and later, American—troops arrived in the region, and the Allies began to take back the Italian Front.
World War I at Sea
In the years before World War I, the superiority of Britain’s Royal Navy was unchallenged by any other nation’s fleet, but the Imperial German Navy had made substantial strides in closing the gap between the two naval powers. Germany’s strength on the high seas was also aided by its lethal fleet of U-boat submarines.
After the Battle of Dogger Bank in January 1915, in which the British mounted a surprise attack on German ships in the North Sea, the German navy chose not to confront Britain’s mighty Royal Navy in a major battle for more than a year, preferring to rest the bulk of its naval strategy on its U-boats.
The biggest naval engagement of World War I, the Battle of Jutland (May 1916) left British naval superiority on the North Sea intact, and Germany would make no further attempts to break an Allied naval blockade for the remainder of the war.
World War I Planes
World War I was the first major conflict to harness the power of planes. Though not as impactful as the British Royal Navy or Germany’s U-boats, the use of planes in World War I presaged their later, pivotal role in military conflicts around the globe.
At the dawn of World War I, aviation was a relatively new field; the Wright brothers took their first sustained flight just eleven years before, in 1903. Aircraft were initially used primarily for reconnaissance missions. During the First Battle of the Marne, information passed from pilots allowed the allies to exploit weak spots in the German lines, helping the Allies to push Germany out of France.
The first machine guns were successfully mounted on planes in June of 1912 in the United States, but were imperfect; if timed incorrectly, a bullet could easily destroy the propeller of the plane it came from. The Morane-Saulnier L, a French plane, provided a solution: The propeller was armored with deflector wedges that prevented bullets from hitting it. The Morane-Saulnier Type L was used by the French, the British Royal Flying Corps (part of the Army), the British Royal Navy Air Service and the Imperial Russian Air Service. The British Bristol Type 22 was another popular model used for both reconnaissance work and as a fighter plane.
Dutch inventor Anthony Fokker improved upon the French deflector system in 1915. His “interrupter” synchronized the firing of the guns with the plane’s propeller to avoid collisions. Though his most popular plane during WWI was the single-seat Fokker Eindecker, Fokker created over 40 kinds of airplanes for the Germans.
The Allies debuted the Handley-Page HP O/400, the first two-engine bomber, in 1915. As aerial technology progressed, long-range heavy bombers like Germany’s Gotha G.V. (first introduced in 1917) were used to strike cities like London. Their speed and maneuverability proved to be far deadlier than Germany’s earlier Zeppelin raids.
By war’s end, the Allies were producing five times more aircraft than the Germans. On April 1, 1918, the British created the Royal Air Force, or RAF, the first air force to be a separate military branch independent from the navy or army.
Marie Curie Helped Win WWI
Second Battle of the Marne
With Germany able to build up its strength on the Western Front after the armistice with Russia, Allied troops struggled to hold off another German offensive until promised reinforcements from the United States were able to arrive.
On July 15, 1918, German troops launched what would become the last German offensive of the war, attacking French forces (joined by 85,000 American troops as well as some of the British Expeditionary Force) in the Second Battle of the Marne. The Allies successfully pushed back the German offensive and launched their own counteroffensive just three days later.
After suffering massive casualties, Germany was forced to call off a planned offensive further north, in the Flanders region stretching between France and Belgium, which was envisioned as Germany’s best hope of victory.
The Second Battle of the Marne turned the tide of war decisively towards the Allies, who were able to regain much of France and Belgium in the months that followed.
The Harlem Hellfighters and Other All-Black Regiments
By the time World War I began, there were four all-Black regiments in the U.S. military: the 24th and 25th Infantry and the 9th and 10th Cavalry. All four regiments comprised of celebrated soldiers who fought in the Spanish-American War and American-Indian Wars, and served in the American territories. But they were not deployed for overseas combat in World War I.
Blacks serving alongside white soldiers on the front lines in Europe was inconceivable to the U.S. military. Instead, the first African American troops sent overseas served in segregated labor battalions, restricted to menial roles in the Army and Navy, and shutout of the Marines, entirely. Their duties mostly included unloading ships, transporting materials from train depots, bases and ports, digging trenches, cooking and maintenance, removing barbed wire and inoperable equipment, and burying soldiers.
Facing criticism from the Black community and civil rights organizations for its quotas and treatment of African American soldiers in the war effort, the military formed two Black combat units in 1917, the 92nd and 93rd Divisions. Trained separately and inadequately in the United States, the divisions fared differently in the war. The 92nd faced criticism for their performance in the Meuse-Argonne campaign in September 1918. The 93rd Division, however, had more success.
With dwindling armies, France asked America for reinforcements, and General John Pershing, commander of the American Expeditionary Forces, sent regiments in the 93 Division to over, since France had experience fighting alongside Black soldiers from their Senegalese French Colonial army. The 93 Division’s, 369 regiment, nicknamed the Harlem Hellfighters , fought so gallantly, with a total of 191 days on the front lines, longer than any AEF regiment, that France awarded them the Croix de Guerre for their heroism. More than 350,000 African American soldiers would serve in World War I in various capacities.
By the fall of 1918, the Central Powers were unraveling on all fronts.
Despite the Turkish victory at Gallipoli, later defeats by invading forces and an Arab revolt that destroyed the Ottoman economy and devastated its land, and the Turks signed a treaty with the Allies in late October 1918.
Austria-Hungary, dissolving from within due to growing nationalist movements among its diverse population, reached an armistice on November 4. Facing dwindling resources on the battlefield, discontent on the homefront and the surrender of its allies, Germany was finally forced to seek an armistice on November 11, 1918, ending World War I.
At the Paris Peace Conference in 1919, Allied leaders stated their desire to build a post-war world that would safeguard itself against future conflicts of such devastating scale.
Some hopeful participants had even begun calling World War I “the War to End All Wars.” But the Treaty of Versailles, signed on June 28, 1919, would not achieve that lofty goal.
Saddled with war guilt, heavy reparations and denied entrance into the League of Nations, Germany felt tricked into signing the treaty, having believed any peace would be a “peace without victory,” as put forward by President Wilson in his famous Fourteen Points speech of January 1918.
As the years passed, hatred of the Versailles treaty and its authors settled into a smoldering resentment in Germany that would, two decades later, be counted among the causes of World War II.
World War I took the lives of more than 9 million soldiers; 21 million more were wounded. Civilian casualties numbered close to 10 million. The two nations most affected were Germany and France, each of which sent some 80 percent of their male populations between the ages of 15 and 49 into battle.
The political disruption surrounding World War I also contributed to the fall of four venerable imperial dynasties: Germany, Austria-Hungary, Russia and Turkey.
Legacy of World War I
The One Thing You Should Know About WWI
World War I brought about massive social upheaval, as millions of women entered the workforce to replace men who went to war and those who never came back. The first global war also helped to spread one of the world’s deadliest global pandemics, the Spanish flu epidemic of 1918, which killed an estimated 20 to 50 million people.
World War I has also been referred to as “the first modern war.” Many of the technologies now associated with military conflict—machine guns, tanks, aerial combat and radio communications—were introduced on a massive scale during World War I.
The severe effects that chemical weapons such as mustard gas and phosgene had on soldiers and civilians during World War I galvanized public and military attitudes against their continued use. The Geneva Convention agreements, signed in 1925, restricted the use of chemical and biological agents in warfare and remains in effect today.
The Spanish Flu Was Deadlier Than WWI
Photo Galleries
French soldiers work together to camouflage a 370 mm railway gun before battle.
French machine gunners take their position in the ruins during the battle of Aisne, in 1917.
French soldiers in Verdun endure the horrors of trench warfare, a strategy that led to rampant disease, shell shock and mass casualties during WWI.
Soldiers in France ready to charge into battle, in an Image titled "Fighting through the night at Mory."
Troops in Passchendaele, Belgium carry a wounded soldier to a medical post for treatment.
A group of Swiss border guards pose behind a fence separating Switzerland and France.
Weathered troops gather behind the French line at Het Sas, near the village of Boezinge in Belgium, after it had been devastated by artillery fire.
Despite destruction all around, the towers of the Our Lady of Reims Cathedral in Reims, France can be seen through the damaged windows of a destroyed building.
Senegalese soldiers serving in the French Army as infantrymen take in a rare moment of rest.
War is all around a little girl, as she plays with her doll in Reims, France, in 1917.
George "Pop" Redding , an Australian soldier from the 8th Light Horse Regiment, is shown picking flowers during the war against the Ottoman Empire in the Middle Eastern theater of World War I. 1918. Palestine.
Some cheerful wounded soldiers wear captured German helmets after the Battle of Neuve Chapelle. The British offensive from March 10-13, 1915 in the Artois region of France lasted only three days, but led to around 11,600 casualties for the British, Indian and Canadian troops, and 10,000 casualties on the German side.
1 / 12: Galerie Bilderwelt/Getty Images
The June 28, 1914, assassination of Franz Ferdinand, heir to the Austro-Hungarian Empire, by Serbian nationalist Gavrilo Princip set off a chain of events that ended in the outbreak of World War I.
A fierce militarist, Wilhelm II encouraged aggressive Austro-Hungarian diplomatic policies following the assassination of Franz Ferdinand. The Kaiser was nominally in charge of the German army, but the real power lay with his generals. As World War I drew to a close, he was forced to abdicate in 1918.
A graduate of West Point and a veteran of the Battle of San Juan Hill, "Black Jack" Pershing was named commander of the American Expeditionary Force when the United States entered World War I in April 1917.
George V assumed the British throne in May 1910, following the death of his father, King Edward VII. He made repeated visits to the front throughout World War I, earning him the deep respect of his subjects.
When Austria-Hungary declared war on Serbia, Russia's alliance with its Balkan neighbor forced it to enter the war against the Central Powers. The tsar assumed control of the Russian army, with disastrous results. In 1917, he was forced to abdicate, and he and his family were executed in 1918.
After the Bolsheviks seized power during the Russian Revolution of 1917, Lenin negotiated the Treaty of Brest-Litovsk. The treaty ended Russia's involvement in World War I, but on humiliating terms: Russia lost territory and nearly one-quarter of its population to the Central Powers.
In 1918, President Woodrow Wilson outlined his vision for a post-war world. He aimed to reduce arms, provide for self-determination and create an association of nations to prevent future wars. His ideas faced opposition at home and abroad and the Treaty of Versailles was never ratified by the United States.
Foch led French forces at the First Battle of the Marne, but was removed from command after the Battle of the Somme in 1916. In 1918, he was named Allied Supreme Commander, coordinating the war's final offensives. Foch was present at the armistice ending the war in November, 1918.
Haig commanded British forces at the Battle of the Somme, losing 60,000 men on the first day. By the end of the campaign, the Allies had lost more than 600,000 men—and advanced fewer than eight miles. Haig rebounded with success in 1918, but remains one of the most controversial generals of the war.
In 1911, Churchill became First Lord of the Admiralty. In this position, he worked to strengthen the British navy. He was pushed out of office after the disastrous 1915 Gallipoli campaign, in modern-day Turkey, which resulted in more than 250,000 Allied casualties.
As prime minister of France from 1917 to 1920, Clemenceau worked to restore French morale and concentrate Allied military forces under Ferdinand Foch. He led the French delegation to the peace talks ending World War I, during which he insisted on harsh reparation payments and German disarmament.
Petain became a national hero in France after his success at the Battle of Verdun during World War I. However, during World War II, Pétain headed the Vichy regime, a pro-German puppet government, and as a result has a mixed and deeply controversial legacy.
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German trenches snaked for hundreds of miles through the countryside near the Somme River.
In the months leading up to the Battle of the Somme in 1916, the Germans constructed trenches and dozens of shellproof bunkers.
In the fall of 1914, British soldiers took refuge near Ypres, Belgium, naming the area "Sanctuary Wood."
In just the first day of the Battle of the Somme, the British Army suffered more than 60,000 causalities, and by the end of the offensive more than 420,000 had been killed.
In April 1917, Canadian forces defeated the heavily entrenched Germans near Vimy, France. Today, the remnants of the German defenses have been preserved with concrete.
Members of the British Royal Navy maneuver a tank, or "landship," over a trench during the 1917 Battle of Cambrai, one of the first successful uses of the tank in World War I.
For nearly four years, the Allies and Germany fought over the Butte de Vauquois. The battles included a deadly series of attacks in which more than 500 mines were exploded beneath trenches, tunnels and buildings in the town.
A company of Canadian soldiers go "over the top" from a World War I trench.
Illustrating the closeness of enemy lines, this British infantry unit fights from a trench that is within 200 yards of German lines.
Communication trenches were constructed at an angle to a defensive trench and often used to transport men and supplies to the front line.
Conditions in the trenches were miserable, with rampant dirt, vermin and disease.
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Men of the Royal Irish Rifles in the trenches during the opening hours of the Battle of the Somme on July 1, 1916.
British machine gunners firing during the Battle of the Somme. The battle was costly in terms of casualties, particularly for the British army who lost 57,470 soldiers on the first day of fighting alone.
An artillery shell is hoisted into position by French and English soldiers. Artillery weapons caused 70 percent of all battle causalities. Heavy artillery included the French 75mm gun and Germany’s devastating 420mm howitzer, which was nicknamed “Big Bertha.”
British troops during the Battle of the Somme, September 1916.
A British soldier gazes out of a dug-out as the body of a dead German soldier lies nearby.
British soldiers advancing under cover of gas and smoke. World War I saw the first use of chemical weapons in battle.
German soldiers lay dead in a shell hole between Montauban and Carnoy.
British and German soldiers wounded on their way to the dressing station near Bernafay Wood at the Battle of Bazentin Ridge.
A German soldier walking through the ruins of Peronne, in northern France, in November 1916.
1 / 10: Royal Engineers No 1 Printing Company/ IWM via Getty Images
Renowned World War I canine hero, Stubby, is photographed on the battlefield wearing a coat, hat and collar, with a gun at his side. Stubby once saved multiple soldiers when he roused them from their sleep after a German mustard gas attack.
The phrase "war dog" is a technical one, and did not apply to U.S. dogs at this time, according to Kathleen Golden, curator of the National Museum of American History's Division of Armed Forces History. "It wasn't until World War II that the United States began using dogs officially," she says. Before then, they were considered "mascots."
In 1922, a bulldog named Jiggs was inducted into the U.S. Marine Corps by General Smedley Butler. He later was promoted to Sergeant Major Jiggs. Germans called the U.S. Marines "Teufel-Hunden," or "Devil Dogs," inspiring Jiggs and a succession of other decorated bulldog mascots.
Belgians decorated their dogs with the hats of German soldiers in 1914, after the dogs were used to move light artillery and machine guns on small carts. Ronald Aiello, president of the United States War Dogs Association, says that German shepherds, bulldogs, Airedale terriers and retrievers were the most commonly used dog breeds during World War I.
Terriers were a preferred breed during the war, Golden says, for their loyalty, rodent-hunting skills and friendly demeanors. New Zealander soldier W. J. Batt poses here with a regimental mascot at Walker's Ridge during the Gallipoli campaign in Turkey on April 30, 1915.
A German Army dog is photographed wearing a hat and glasses, with a pair of binoculars around his neck. The Germans began using dogs in an official capacity during wartime in the late 19th century, not long before the start of World War I. The Allied Forces had at least 20,000 dogs on the battlefields of World War I, while the Central Powers—primarily Germany—had about 30,000.
Golden says that during World War I, "Dogs were primarily used as messengers." On July 5, 1916, this messenger dog used by the British Army in Flanders, Belgium runs to the front with urgent messages.
Message dogs were often outfitted with collars that had attached cylinders. Here, a sergeant of the Royal Engineers places a message into the cylinder on August 28, 1918, at Etaples, France.
Messenger dogs such as "Wolf," an Alsatian, often had to negotiate dangerous obstacles, including barbed wire entanglements. Here, Wolf clears a fence at the Western Front in Flanders, Belgium.
While horses were often used to haul heavy guns and other equipment, teams of dogs would also be recruited for hauling weapons and other objects. Italian soldiers oversee dogs performing such work in 1917.
Dogs, with their keen sense of hearing, endured frequent exposure to gunfire and other loud sounds during World War I. This dog belonged to Captain Richardson of the U.K., who brought his canine companion with him to the trenches in 1914.
Visual cues were critical for dogs on missions during World War I. German soldiers in 1916 appear to point something important out to a dog serving as a messenger in the field.
World War I dogs, especially terriers, proved to be productive rat hunters. That was an invaluable skill in the war's rat-infested trenches. Here, a terrier poses with some of his kill near the front lines of France in May 1916.
In France in 1915, a dog is dressed up as a German soldier—complete with pipe and goggles—to the amusement of soldiers marching by.
Resting in a wooden building at an airfield, German military pilots smoke pipes and chat alongside their canine companion. Dogs were great "morale boosters" for troops on both sides of the battlefields during World War I, Golden says.
Mascots such as "Doreen," an Irish wolfhound, were often brought to memorial services. World War I was one of the deadliest conflicts in human history, with military and civilian casualties estimated at over 16 million. Doreen was a mascot of the 1st Battalion of the Irish Guards.
These dogs are armed with first aid equipment and stimulants as they help search for wounded soldiers in no man's land.
Aiello explains that "dogs were trained to find the wounded or dying soldiers on the battlefield. This would let the medics know who was still alive so the injured could get immediate medical treatment." This dog finds a wounded soldier lying under a tree in Austria, July 1916.
A French Red Cross dog demonstrates his climbing skills by scaling a 6-foot-high wall. Dogs often had to maneuver over comparable obstacles while searching for wounded soldiers.
"I think that Red Cross dogs were the heroes of World War I," Aiello says. The dogs would not only locate wounded soldiers, as shown in this 1917 image, they would also help to transport them from the battlefield.
A French sergeant and a dog, both wearing gas masks, marched to the front lines. Many dogs were injured by toxic gas. Still others died from exposure to chemical agents like chlorine and phosgene.
During the spring of 1917 a French messenger dog wearing a gas mask runs through a cloud of poisonous gas.
German soldiers and their dogs wore gas masks as well. The Germans were the first to use such chemical weapons during this war, releasing clouds of poisonous chlorine at Ypres, Belgium in April 1915.
A German Army dog manages to leap over a trench in France while delivering a message from one outpost to another. Thousands of dogs died while serving in World War I, often while delivering messages. Once a message was delivered, the dog would be turned loose to move silently to a second handler.
Two soldiers captured a pair of German dogs during World War I. The canines were named Crown Prince and Kaiser Bill. The men, wounded in battle, posed with the dogs before returning with them to the United States.
This dog, photographed in 1915 in a trench at Flanders, Belgium, and other military dogs have safeguarded and aided people on battlefields from before World War I to the present, says Aiello, who was deployed to Vietnam in 1966 with his own canine companion, Stormy. "They protect our troops and would die for us."
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This postcard from 1917 shows a U.S. Army balloon and hanger leaving its port. Army balloons were primarily used to scout enemy territory and to transport equipment. However, they were easily shot down and eventually replaced with planes.
This illustration portrays the many different types of planes that were used by the British Royal Air Force during World War I, the first military conflict in which aircraft played a critical role.
A green and yellow RAF SE-5a biplane on display at the Abbotsford International Air Show in British Columbia, Canada.
A naval airship hovers over the Dardanelles. In an attempt to gain control of Constantinople, the Allies battled Turkish forces on the Gallipoli Peninsula. The naval assault eventually stalled, with Britain forced to evacuate their forces.
A photo of a 1915 World War I French aircraft carrier. Carriers made a huge difference in the war, allowing forces to execute missions without having to depend on local bases.
A photograph from 1914 portrays a German warship making its way through the sea.
Guns mounted aboard ships like the Wyoming allowed troops to take out enemies, while still remaining at a distance.
An illustration by Willy Stower depicts men aboard a World War I submarine. The introduction of unrestricted submarine warfare was a major threat during the Great War.
Two German U-boats sunk during the Great War washed up on shore at the Cornish Coast in Falmouth, England.
A field gun sits on display at a wooden area that was once occupied by U.S. Marines during the 1918 Battle of Belleau Wood, which was an Allied response to the German spring offensive.
Soldiers set up a British big gun in preparation for a German advance. Machine guns played a large role in the trench warfare, allowing men to fire hundreds of rounds per minute.
Soldiers of the U.S. Army Ordnance Department display the damage done to their body armor after a firing test at Fort de la Peigney in Langres, France.
The introduction of tanks played a large role in the Great War, as they helped to end the stalemate of trench warfare on the Western Front. Here officers inspect a German A7V tank that was captured in Villers-Bretonneux, France.
1 / 13: Lake County Museum/CORBIS
One of Germany’s most feared weapons during World War I was its fleet of submarines that targeted ships with torpedoes. A Royal Navy volunteer reserve lieutenant, Norman Wilkinson, came up with a radical solution: Instead of trying to hide ships, make them conspicuous. Shown: British Gunboat HMS Kildangan, 1918
Ships’ hulls were painted with startling stripes, swirls and irregular abstract shapes that made it more difficult to figure out the ship’s size, speed, distance and direction. Shown: 1st Aero Squadron
Here is an exterior view of a wooden ship built for the United States Shipping Board Emergency Fleet Corporation, by the Pacific American Fisheries, in Bellingham, Washington, 1918.
When submerged, the Germans’ only way of sighting a target was through the periscope, which they could only poke through the water for a fleeting moment. Contrasting patterns helped throw off Germans' quick calculations when aiming a torpedo. Shown is the U.S.S. Minneapolis painted in dazzle camouflage, Hampton Roads, Virginia, 1917.
A U.S. warship with dazzle camouflage heading to Europe from the USA, circa 1914-1918.
The USS Nebraska (BB14) is shown with camouflage paint, 1918.
The USS Leviathan docked at Pier Number 4, Hoboken, New Jersey, April 1918.
British WWI transport, Osterle, camouflaged with zebra stripes, November 11, 1918 in New York Harbor. Studies have shown that zebra's stripes can serve the same purpose, making a herd appears to a predator as a chaotic mess of lines from a distance.
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Now a fashion icon, the trench coat first gained popularity among British officers during World War I because of its functionality. The water-resistant overcoats proved superior to the standard wool coats in repelling the rain and chill of the trenches—from which the garment gained its name.
Although the idea of shifting time dated back centuries, Daylight Saving Time was first implemented in Germany in April 1916 as a wartime measure to conserve coal. Weeks later, the United Kingdom and other European countries followed suit.
Doctors rarely performed blood transfusions prior to World War I. However, following the discovery of different blood types and the ability of refrigeration to extend shelf life, a U.S. Army doctor consulting with the British Army, established the first blood bank in 1917 on the Western Front.
During a European tour in 1914, Kimberly-Clark executives discovered a material made from processed wood pulp that was five times more absorbent than cotton and cost half as much to produce. With cotton in short supply during World War I, the company trademarked the creped wadding as Cellucotton and sold it to the American military for surgical dressing. Red Cross nurses, however, found another use for the cotton substitute as makeshift sanitary pads.
Kotex was not the only product that Kimberly-Clark developed from Cellucotton. After experimenting with a thin, flattened version, the company launched it in 1924 as a disposable makeup and cold-cream remover under the brand-name “Kleenex.” When women started complaining about their husbands blowing their noses in their Kleenex, Kimberly-Clark repositioned the tissues as handkerchief alternatives.
Joseph Hubertus Pilates, a German bodybuilder, was interned as an enemy alien after the outbreak of World War I. During his more than three years at the internment camp, Pilates developed a regimen of muscle strengthening through slow and precise stretching and physical movements. He further aided rehabilitation of bed-ridden internees by rigging springs and straps to their headboards and footboards for resistance training.
During the war, the British military was in search of harder alloys for their guns so they would be less susceptible to distortion from the heat and friction of firing. English metallurgist Harry Brearley discovered that adding chromium to molten iron produced steel that wouldn’t rust.
Although not called the zipper until the B.F. Goodrich Company coined the term in 1923, the “hookless fastener” was perfected by Gideon Sundback during World War I. The first major order of zippers came for money belts worn by soldiers and sailors who lacked uniform pockets. Zippers began to be sewn into the flying suits of aviators and took off in popularity in the 1920s.
Prior to World War I, most men used pocket watches on chains as their time keepers, but they proved impractical in trench warfare. Wristwatches also proved necessary for aviators who needed both hands at all times. After proving their utility in warfare, wristwatches gained acceptance as a men’s fashion accessory.
Fewer than 15 years after Orville Wright soared over the dunes of Kitty Hawk, he participated in the American military’s first experiments with unmanned aircraft. Charles Kettering supervised the experiments and, in 1918, successfully tested an unmanned aerial torpedo that could strike a target at a distance of 75 miles.
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