On 21 November 1920, more than 30 people were killed or fatally wounded on the streets of Dublin. That is just about all there is total agreement on, even at the remove of a century. In the morning, more than fifteen men were shot dead or fatally wounded, while 14 civilians would die at Croke Park in later violence, and 3 prisoners in Dublin Castle would be dead by the end of the day. This is the story of a day of real violence in the Irish capital, exploring how it happened and how it has been remembered.