The question, "What were the causes of World War I?," has become one of the classic historical debates of which there seem to be endless permutations. In the past 90 years historians, journalists, and politicians have offered many more or less rational explanations for the war. Although at least some of the usual "causes" assigned to the war offer relatively straightforward threads of argument, the harmony created when these causes are assembled and prioritized is particularly complex. Given this scenario, the analysis of the causes of World War I by students is an excellent opportunity to hone such cognitive skills as comprehension, interpretation, analysis, explanation, refutation, and synthesis. In this article, the author describes a semester-long project which he has over the years developed to allow students in certain modern history classes to analyze the causes of World War I through a number of activities. This project provides students an in-depth examination of a critical event in history while developing their cognitive abilities--which after all is the goal of many history courses. Instructors might wish to consider utilizing this project for upper-level courses focused on 20th Century Europe; Europe from 1870 to 1914; World War I; and similar themes. (Contains 12 notes and 39 resources.)