The October Revolution occurred in November of 1917 according to the Gregorian calendar. At the time, the Russian Empire was still using the Julian calendar. Thus they dated the Great October Socialist Revolution (or October Uprising, or Red October) to October 25, 1917, whereas the rest of the West dated it to November 7, 1917. It followed the February Revolution of the same year and established the communist government that would eventually lead to the USSR.
The Pre-War Russian Empire was weak and technologically backward compared to the rest of Europe. Its degree of industrialization was low, and there was a great deal of social, economic, and political division. The First World War was increasingly unpopular, and there were a number of scandals surrounding the monarchy. Following mass demonstrations and clashes between rioters and the police in the capital and its vicinity, the monarchy was deposed and replaced by a provisional government in February of 1917.
The provisional government, an executive and an assembly, was made up of liberals and socialists who wanted reform and the aristocracy. This government was weak and rife with dissension. It continued pursuing the increasingly unpopular war and postponed land reform. Further, chaos in industry and transportation led to mass unemployment and increasing difficulty procuring food.
In September and October, more than a million workers took part in mass strikes across the nation then took control of production and distribution in the factories, mines, plants and railroads. There were thousands of peasant uprising against landowners, to which the provisional government responded by sending troop detachments. The army and navy announced through their elected representatives that they no longer acknowledged the authority of the provisional government and would not follow its commands. The [[soviet]']s democratically elected (unlike the provisional government, which continued postponing elections) local councils increased in popularity.
The provisional government weathered a crisis in the summer of 1917 and elected a new government. However, instability continued to increase, and troops were called in as the new executive feared a coup, although it may have been an attempted coup on the part of the troops' leader. However, Bolshevik control over the railroads was instrumental in stopping the troop advance. Promising peace, bread, and land, the Bolsheviks staged their own coup. Led by Trotsky, the Red Guard seized control of Petrograd, while a warship sympathetic to the Bolsheviks, the Aurora, trained its guns on the Winter Palace, headquarters of the provisional government. The Bolsheviks stormed the palace and arrested the provisional government.
The Congress of Soviets endorsed the Bolshevik actions, cementing their seizure of power. Dissenting parties disagreed and stormed out. The Congress elected a government, which began arresting political opponents. The new government then nationalized all banks and seized private accounts, seized all factories and land, seized the churches and their assets, and all foreign debts were abandoned.