Howitzers, mortars, and cannons were all types of artillery used in World War I.

The rifle was the primary infantry weapon used by soldiers during World War I.

Great Britain was the first country to use tanks in World War I.

The German submarine U-20 sank the RMS Lusitania in 1915.

Mustard gas, chlorine gas, and phosgene gas were all types of chemical weapons used in World War I.

The Fokker Dr.I was the British fighter plane that was flown by aces like Manfred von Richthofen.

Battleships, destroyers, and cruisers were all types of naval ships used in World War I.

The Schlieffen Plan was the German military strategy that involved a rapid advance through enemy territory.

Fighter planes, bomber planes, and reconnaissance planes were all types of aircraft used in World War I.

John J. Pershing was the American general who led the American Expeditionary Force in World War I.

Barbed wire, trenches, and dugouts were all types of trench warfare used in World War I.

The Treaty of Versailles was the peace treaty that ended World War I.

Lewis gun, Vickers machine gun, and Maxim gun were all types of machine guns used in World War I.

Alfred von Schlieffen was the German military leader who was responsible for the Schlieffen Plan.

High-explosive shell, shrapnel shell, and gas shell were all types of artillery shells used in World War I.