Overthrow of the Russian monarchy and withdrawal from World War I.
In 1917, Nicholas II abdicated (step down) from his thrown and gave by control of the monarchy for himself and his son. This allowed for a new nationalist government to take control.
The new government was then overthrown by the Lenin led Communist Party.
In regards, to World War I, after Nicholas stepped down, Russia signed a peace treaty with Germany and left the war before their other allies. They lost western lands in Russia but were able to save their military from a horrible showing on the Eastern Front.
The division of korea to north and south korea.
