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).
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

ruin.

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

terrible.

Noun

political unit made of people who share a common territory.

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.