- The Western Front was the main theater of operations during World War I, and saw some of the most intense and bloody fighting of the war. The fighting took place primarily in France and Belgium, and involved the armies of Germany, France, Britain, and the United States.
Eastern Front
- The Eastern Front was another major theater of operations during World War I, and involved the armies of Russia, Germany, and Austria-Hungary. The fighting took place primarily in eastern Europe, and was characterized by large-scale cavalry battles and trench warfare.
Italian Front
- The Italian Front was a secondary theater of operations during World War I, and involved the armies of Italy and Austria-Hungary. The fighting took place primarily in the Alps and the Po Valley, and was characterized by mountain warfare and trench warfare.
Middle Eastern Front
- The Middle Eastern Front was a secondary theater of operations during World War I, and involved the armies of Britain, France, and the Ottoman Empire. The fighting took place primarily in the Middle East, and was characterized by desert warfare and trench warfare.
African Front
- The African Front was a minor theater of operations during World War I, and involved the armies of Britain, France, Germany, and Belgium. The fighting took place primarily in German East Africa, Cameroon, and Togoland, and was characterized by guerrilla warfare and trench warfare.