World War I was the catalyst for more major military technological innovations than any other war in history.
Balloons had been used in earlier wars, but serious directed and controlled flight above the ground was still in its infancy when World War I broke out. Germany used their Zeppelin dirigibles in a number of high-altitude raids on Paris and London, but long before the end of the war the Germans abandoned mass Zeppelin raids. Rapid improvements in Allied airplanes enabled them to climb to the same altitude, firing tracer machine-gun bullets into the hydrogen-filled gas bags of the dirigibles, turning them into aerial infernos. War in the air had little influence on the outcome of World War I. Most aerial warfare consisted of individual combats, bearing little relation the ground battles. Bombing did not seriously damage any war industry, and communications and supply lines on the ground were never significantly disrupted.
Americans in the Revolutionary and Civil wars pioneered submarine warfare. However effective
military submersibles only made their appearance in World War I. Before 1914 German naval
intelligence realised the potential of the submarine as a means of counteracting Britain's
dominance of the sea. This theory almost succeeded, the submarine campaign of 1917 nearly forced
Britain out of the war, ultimately submarines no longer posed a serious threat.
A dramatic and important a new weapon, the tank, also demonstrated a potential that would come
to be fully realised only in subsequent warfare. By the end of World War I the tank was becoming a
major force in ground battles. Although slow, cumbersome, and vulnerable to hostile artillery, it
could provide mobility and firepower to the attacker.
Poison gas was, largely because of its stealth and its asphyxiating fumes, the most
terror-inspiring of all weapons of the war. Countermeasures soon reduced poison gas to little more
than a means of harassment, but its deadly potential led to an international agreement, the Geneva
Protocol of 1925, banning poison gas as a means of warfare.
Like the airplane and the submarine, the machine gun was an American invention that was improved in Europe. Early in World War I its value as a defensive weapon was demonstrated. The Germans ultimately recognised the offensive potential of the machine gun and pioneered the development of light machine guns to provide mobile firepower within every squad.
New developments immediately before World War I, like high-explosive shells that could sweep large areas with destructive blasts and jagged splinters of steel, restored artillery to its place as the arbiter of battles. Tube artillery weapons also approached their full potential of lethality during World War I. The French 75mm field gun, developed in 1897 remained a useful weapon when World War II broke out in 1939.
Field telephones not only revitalised artillery, but they provided instantaneous communication between commanders and field units. Few improvements have been made in field telephones since World War I; improvements in radio transmission, however, have been continuous, with the future potential of electronics in warfare still unlimited.
The increased technology of World War I had greatly expanded the potential for killing, but it was also hoped that this "war to end all wars" had served as a lesson to nations and that future bloodshed could be avoided. World War I caused great destruction: about ten million people were killed, and property worth millions was destroyed.