The correct answer is Russian Revolution
The Russian Revolution of 1917 was one of the main events of the 20th century. This event broke out during the First World War (1914-1918), despite its antecedents going back to 1905, when the first revolutionary attempt took place, which had as its trigger the remarkable episode known as Bloody Sunday.
The main aspect of the Russian Revolution is that it was guided by communist doctrine, developed by the German philosopher Karl Marx in the 19th century - with the proviso that such doctrine was complemented and added to a strategic plan by the one who became the most important leader of the revolution: Lenin.