Winter palace and city's main square are usually associated with revolutionaty events of October 1917, but there is a date of no less importance, January 9, 1905, known as a "Bloody Sunday". On this day the unarmed demonstrators were fired upon by soldiers of the Imperial Guard as they marched towards the Winter Palace to present a petition to Tsar Nicholas II of Russia. This event triggered the Revolution of 1905-1907 and, consequently the February and the October Revolutions.
The storming of Winter Palace was one of the key ivents of the October Revolution. The Bolsheviks seized the residence of the Provisional Government on the night from October 25 to October 26, 1917, and, as a result, the Provisional Government was overthrown and its members were arrested.