Key information
Main belligerents
The war was fought between two opposing blocs:
Allied Powers: Included Britain (and its empire, including India and Australia), France, and Russia. The United States joined the Allies in 1917. Russia withdrew from the war after its revolution later that year.
Central Powers: Led by Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria.
Causes
Multiple long-term factors and one immediate trigger led to the war:
Assassination of Archduke Franz Ferdinand: The assassination of the Austro-Hungarian heir by a Serbian nationalist in June 1914 was the direct trigger. This prompted Austria-Hungary to declare war on Serbia. This started a chain reaction due to existing alliance systems.
Alliance systems: Mutual defense treaties divided Europe into opposing camps: the Triple Entente (Britain, France, Russia) and the Triple Alliance (Germany, Austria-Hungary, Italy).
Imperialism: Competition for colonies and resources, especially in Africa and Asia, increased tensions among European powers.
Militarism and arms race: An arms race, particularly a naval one between Germany and Britain, promoted military power and made conflict seem more likely.
Nationalism: The desire for self-determination among ethnic groups within empires, particularly the Slavic peoples in the Balkans, caused unrest. It also contributed to the initial crisis involving Serbia.
Key events and characteristics
War fronts: The conflict occurred across Europe, the Middle East, and Africa. The main theaters were the Western and Eastern fronts.
Trench warfare: The Western Front became defined by trench warfare, a "war of attrition." It resulted in many casualties for minimal territorial gains.
New technologies: WWI saw new and deadlier weapons. These included machine guns, long-range artillery, tanks, airplanes, and chemical weapons like poison gas.
War's end: Following a German offensive that failed in the spring of 1918, a decisive Allied counterattack led to the collapse of the Central Powers. The war ended with an armistice signed on November 11, 1918.
Consequences
Human cost: The war was one of the deadliest in history, with an estimated 20 million deaths (8.5 million military, and many civilian deaths from war-related causes and disease) and another 21 million wounded.
Political impact:
*Four major imperial dynasties collapsed: the Russian, German, Austro-Hungarian, and Ottoman Empires.
*The map of Europe was redrawn, creating new nation-states like Poland, Czechoslovakia, and Yugoslavia.
*The United States emerged as a major world power.
*The Treaty of Versailles imposed harsh terms on Germany. This contributed to economic instability and the rise of the Nazi Party, which would lead to World War II.
Social and economic changes:
Women entered the workforce in large numbers to replace men, which helped advance women's rights.
The war's economic cost led to debt and inflation for European countries. The United States experienced an economic boom.
Technological advancements made during the war later influenced civilian industries and medicine.
Written on Sept. 1, 2025, 7:11 a.m.