Trench warfare, as practiced by these Russian soldiers awaiting a German assault, characterized World War I.
Photograph by George H. Mewes, National Geographic

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  • On August 3, 1914, France and Germany declared war on each other. This broadened the conflict that began a week earlier with the assassination of Austrian Archduke Franz Ferdinand by Yugoslavian nationalist Gavrilo Princip. The conflict soon escalated into World War I.
    The so-called “Great War” soon grew even more global. The war was dominated by European empires, specifically those of the Allied Powers (the British Empire, France, and the Russian Empire) and the Central Powers (the German Empire, Austro-Hungarian Empire, and Ottoman Empire). Soon, however, nations such as the United States, Japan, and Greece (on the Allied side); and Bulgaria and Darfur (on the Central side) joined the conflict. World War I saw battles throughout Europe, the Middle East, Africa, China, and the island of New Guinea.
    World War I introduced many horrific tactics associated with modern warfare: trenches, gas warfare, and the use of machine guns. The conflict lasted about four years, cost more than 16 million lives, and resulted in the destruction of four empires (Russian, German, Austro-Hungarian, and Ottoman).
  • Term Part of Speech Definition Encyclopedic Entry
    assassination Noun

    murder of someone of political importance.

    associate Verb

    to connect.

    broaden Verb

    to become or make wider.

    conflict Noun

    a disagreement or fight, usually over ideas or procedures.

    declare Verb

    to state clearly, in formal terms.

    destruction Noun


    dominate Verb

    to overpower or control.

    empire Noun

    group of nations, territories or other groups of people controlled by a single, more powerful authority.

    escalate Verb

    to increase.

    horrific Adjective


    nation Noun

    political unit made of people who share a common territory.

    Encyclopedic Entry: nation
    nationalist Noun

    person who identifies strongly with promoting the independence (and sometimes the superiority) of their nation.

    trench Noun

    long, deep depression, either natural or man-made.

    war Noun

    large-scale armed conflict.

    weapon Noun

    tool to hurt or combat an opponent.

    World War I Noun

    (1914-1918) armed conflict between the Allies (led by the United States, the United Kingdom, and France) and the Central Powers (led by Germany and Austria-Hungary). Also called the Great War.