Northern Ireland, also known as Ulster is the north-eastern part of Ireland. It is one of the four Countries of the United Kingdom, one of the four provinces of Ireland, and the only part of Ireland within the UK. The Northern Irish IRA did terrorism in a big way before and after the British army shot dead 14 Republican protesters in Derry on a day now know as Bloody Sunday] in 1972. Terrorism involving the Roman Catholic IRA and the Protestant UDA went on for about thirty years between around 1968 and the start of the 21st Century and over that time about 3,000 people were killed. The number of victims was roughly similar to the number killed in the September 11, 2001 attacks but the deaths were more spread out.