This document provides background on the events leading up to World War 1. It discusses the rise of nationalism and imperialism in Europe, which led to increased tensions over territorial disputes. It also examines the system of alliances between European powers and the rise of militarism, as countries built up their armed forces. When the Archduke of Austria-Hungary was assassinated, the complex system of alliances drew the major European powers into war. The document summarizes the initial outbreak of fighting and the onset of trench warfare on the Western Front.