Bloody Sunday occurred on January 22nd, 1905 in St. Petersbrg, Russia.  It happened during a peaceful protest with unarmed citizens, mostly poor laborers, against Tsar Nicholas II over undesirable Tsarist policies.  Multiple groups, lead by Georgy Gapon, a Russian Orthodox Priest, were converging on the Winter Palace when the massacre took place.  The plan was for the Tsar to see the thousands of people protesting his policies so that he would consider changing them, but unbeknownst to them, he was not their.  Upon their approach to the Palace, Imperial Guards shot off warning shots for them to turn around and leave, but they didn’t.  Shortly after that, shots were fired into the crowd towards Gapon, killing about 40 people around him.  There are several different reports that recorded anywhere from 100 to 3,000 deaths.  Following this tragedy, popularity for the Tsar regime dropped sharply.  Many credit it this event as one of the sparks for the Revolution of 1905.

The December before in 1904, there was a similar strike at the Putilov Plant lead by Georgy Gapon, where workers protested for better wages, conditions and working hours.  In this protest there were no deaths or violence, but it was obvious that there was a sense of displeasure with the Tsarist regime.  Further protests and political actions were surely expected in the future.

http://novaonline.nvcc.edu/eli/evans/HIS242/Notes/Gapon.html

http://www.history.com/this-day-in-history/bloody-sunday-massacre-in-russia