At the start of the war, the largest of the European belligerents were all colonial powers -- they had people and valuable assets stationed in countries all over the Earth. These multinational interests, along with overseas alliances and the modernization of sea transport, are what put the "world" in World War I. Enemy nations attacked each other's colonies and fleets, and laborers and soldiers were recruited from colonized countries, and brought to the front lines. Allied countries -- many former colonies -- shipped soldiers and supplies into battle, coordinating with their European counterparts. And, despite the fact that the Western Front is the best-known theatre of World War I, the Eastern Front -- the battle between the Central Powers and the Russian Empire -- was equally devastating and consequential, resulting in millions of deaths and divisions that continue to affect the region to this day. In this entry, a look at some of the diverse nations and cultures involved in the war. On this 100-year anniversary, I've gathered photographs of the Great War from dozens of collections, some digitized for the first time, to try to tell the story of the conflict, those caught up in it, and how much it affected the world.