A crowd of about 20,000 people demonstrated in 1905 in St. Petersburg to appeal for Workers' reforms . This demonstration led to Bloody Sunday .
This excerpt is about the Russian Revolution of 1905. It was a series of events that led to a Constitutional Reform.
The manifestation the excerpt mentions happened during a strike. Workers left their workplace to deliver a petition to the Tsar, in front of the palace. At a certain point, the guards opened fire, which caused between 200 and 1000 deaths.