What are some examples of people outside Europe participating in the war?

- The Ottoman Empire, which was centered in modern-day Turkey, fought on the side of the Central Powers. The Ottomans had been in decline for several decades, but they still had a large and powerful military. They fought against the British, French, and Russian empires in the Middle East and North Africa.

- Japan fought on the side of the Allied Powers. Japan had been rapidly industrializing in the late 19th and early 20th centuries, and it had become a major naval power. Japan fought against the German Empire in the Pacific Ocean, and it also sent troops to fight in Europe.

- The United States entered the war on the side of the Allied Powers in 1917. The United States had been reluctant to enter the war, but it was eventually drawn in by the German Empire's unrestricted submarine warfare. The United States provided the Allied Powers with much-needed supplies and troops.

- China entered the war on the side of the Allied Powers in 1917. China had been in a state of civil war for several years, but it was able to unite behind the war effort. China sent troops to fight in Europe, and it also provided the Allied Powers with supplies.