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The Spartacist uprising takes place and is crushed by the German government, marking the end of the German Revolution.
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The Polish–Soviet War begins with border clashes between the two states.
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Creation of the Free City of Danzig which was neither approved by Germany nor Poland.
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Hungary signs the Treaty of Trianon with the Allied powers. The treaty regulated the status of an independent Hungarian state and defined its borders. The United States did not ratify the treaty and later makes a separate peace treaty with Hungary.
