The document summarizes the key causes of World War 1 in 3 points: 1. Rivalries and tensions within the alliance system in Europe increased the risk of war breaking out. Countries formed alliances that put them against each other and tensions rose due to imperialist rivalries over colonies and territory. 2. Internal dissent and unrest within countries from groups like communists, socialists, and labor unions added to tensions and instability in European societies. 3. As tensions rose, countries engaged in militarism and a buildup of their armed forces through conscription and increasing the size of their militaries, which further increased the risk of war.