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Content Overview

Unit 7: c. 1900-Present

World War 1

Causes of the War

The MAIN Causes


European nations kept competing with each other by making larger weapons 


Europe had 2 main alliances (Triple Alliance & Triple Entente). A small rivalry between 2 nations would lead to a huge war between each nation's alliances


European nations competed for colonies abroad. The main rivalries were between Germany and Britain/France


European nations had huge popular nationalist sentiment → The people would cheer on their nation to win the war without dropping out

The 2 Alliances

Triple Alliance
(Central Powers)

Triple Entente



The Start of the War

Archduke Franz Ferdinand of Austria-Hungary was visiting Sarajevo (in his Serbian province)

Gavrilo Princip, member of Serbian independence terrorist group, shot Ferdinand

Austria-Hungary declared war on Serbia after Serbia refused to allow Austria-Hungary to investigate the crime

Britain declared war on Germany

Germany joined the war as it was Austria-Hungary's ally & declared war on Russia & France

Russia declared war on Austria-Hungary to protect the Serbs

The Middle of the War

German Battle on Western Front (with France)

Germany moved westward through Belgium to attack France

France stopped Germany at River Marne

Battle was a stalemate for 4 years due to trench warfare

German Battle on Eastern Front (with Russia)

Germans attacked Russia

Russia was so devastated from the war, and this allowed it to have an internal communist revolution (1917)

Russia's new communist government withdrew from the war in the Treaty of Brest-Litovsk (1918)

Japan's Entry into the War

Germany had a small presence in East Asia, where it controlled the Shandong peninsula in China

Germany was distracted with WW1 in Europe, so Japan could take over German possessions in East Asia to expand its influence there

Japan declared war on Germany (on the side of the Allies) in August 1914

The End of the War

Why did the US Join the War?

German U-boats sunk many ships

German submarines sunk a lot of American ships, especially the British ship Lusitania in 1915 with 128 US citizens on board

US gave loans to Allies

US gave many loans to the Allies (especially Britain & France), so it only made sense for the Allies to win

Zimmerman Telegram

Germany asked Mexico to join WW1. In exchange, Germany would give Mexico the territories lost to US in the Mexican-American War (1846-48)

Allies' Lack of Troops

Russia withdrew from WW1 in mid-1917 (officially in 1918) → Germany could focus all troops on Western front → US needed to supply troops to Western front

On April 6, 1917, the US joined World War 1 on the side of the Allies (with Britain & France)

End of the War

At the beginning of the war (Aug 1914), Britain imposed a naval blockade on Germany

With US troops helping the Allies, Germany didn't have enough resources to attack the Allies (and the naval blockade was also depleting its resources)

The Central Powers surrendered to the Allies (Nov 11, 1918)

Post-war Situation

Woodrow Wilson's Fourteen Points

Readjust borders in Europe to give each ethnic group its own state

Free trade in the seas & open diplomacy (no secret treaties)

League of Nations (an int'l group of nations to foster int'l cooperation) 

Wilson drafted the 14 points as a set of agreements to implement after WW1. The main idea is self-determination, the idea where each ethnicity can choose its own government. Colonial subjects interpreted this differently, thinking they should get independence. 

Treaty of Versailles (1919)

Germany forced to pay Allies $33 billion in reparations

Creation of an int'l organization called League of Nations

Restructured many land borders: Germany ceded all colonies

Other Post-WW1 Treaties & Developments

Creation of Turkey

In 1923, Ottoman Empire ended, and the nation of Turkey was created. Ottoman military general Mustafa Kemal was the 1st president (Ataturk)

Mandate System

Ottoman empire ended (1923) → Arab states south of Turkey had no gov → Britain & France made mandate system there (similar to imperialism)

Influenza Pandemic of 1918

An influenza virus originated in Spain & spread via WW1 soldiers → Became global pandemic in 1918, killing 20 million

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