Bloody Sunday was an event which took place in London, England on 13 November 1887, when a crowd of marchers protesting about unemployment and the Irish Coercion Acts, as well as demanding the release of MP William O'Brien, clashed with the Metropolitan Police. The demonstration was organised by the Social Democratic Federation and the Irish National League. Violent clashes took place between the police and demonstrators, many "armed with iron bars, knives, pokers and gas pipes". A contemporary report noted that 400 were arrested and 75 persons were badly injured, including many police, two policemen being stabbed and one protester bayonetted.

Trafalgar Square is a public square in the City of Westminster, Central London, established in the early 19th century around the area formerly known as Charing Cross. The square's name commemorates the Battle of Trafalgar, the British naval victory in the Napoleonic Wars over France and Spain that took place on 21st October 1805 off the coast of Cape Trafalgar.