What happened in Europe that cause the Red Scare in the US in the 1920s?

The First Red Scare occured during the years 1917-1920 and was caused by the Russian Revolution of 1917 and the impact of World War One in America. The Red Scare was the name given to the period of anti-radical hysteria and the fear that anarchists, socialists and communists were conspiring to start a workers revolution in the United States of America. The First Red Scare was sparked by fear and suspicion, widespread strikes and a series of terrorist attacks in the homeland.

Explanation:

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