The Russian Revolution, a pair of revolutions that shook Russia in 1917, plunged the country into a civil war and prompted hundreds of thousands from the Tsarist society's upper ranks to flee for their lives.
The main events of both revolutions took place in Petrograd, now known as St. Petersburg.
The first one, known as the February Revolution, lasted from March 7 to March 16 (or February 22 to March 3 in the Julian calendar) 1917.
The second is widely known as the October Uprising or Red October, with the main events starting with an armed insurrection in Petrograd on November 7 [October 25] 1917.
This year, Russia marks the centenary of the events that changed the country forever.