The largest of the current 16 missions is in the Democratic Republic of Congo, with more than 22,000 personnel.
The Department of Peacekeeping Operations also runs one political mission, in Afghanistan.
Currently there are approximately 118,792 peacekeeping personnel from 121 countries.
1993 - At least 16 peacekeepers are killed in Cambodia, allegedly by Khmer Rouge guerrillas.
June 5, 1993 -
In Mogadishu, Somalia
, forces loyal to warlord Mohammed Farah Aidid ambush and kill 23 Pakistani peacekeepers
September 5, 1993 - Seven peacekeepers from Nigeria are killed in Mogadishu, Somalia, in an ambush by gunmen loyal to Mohammed Farah Aidid.
May 17, 1994 - Five UN peacekeepers from Nepal are killed in a gun battle in Mogadishu, Somalia.
May 4, 2000 - In Sierra Leone, seven peacekeeper troops from Kenya are killed by rebels.
February 25, 2005 - Seven peacekeepers from Bangladesh are killed in an ambush in the Democratic Republic of the Congo.
January 23, 2006 - Rebels in the Democratic Republic of the Congo kill eight peacekeepers from Guatemala.
June 24, 2007 -
Six UN peacekeepers are killed in southern Lebanon by a car bomb
June 8, 2012 - Armed assailants kill seven peacekeepers in the Ivory Coast.
April 9, 2013 - Five UN peacekeepers from India are killed in South Sudan.
July 13, 2013 - Gunmen ambush a peacekeeping force in the Darfur
region of Sudan, killing seven Tanzanian troops.
September 18, 2014 - Five United Nations peacekeepers from Chad are killed and three others are injured when a UN vehicle hits a homemade bomb in northern Mali.
October 3, 2014 - Nine UN peacekeepers from Niger are killed in an ambush in Mali, when their convoy is attacked near Menaka, in the country's eastern Gao region, by heavily armed men on motorcycles.
July 2, 2015 - Six UN peacekeepers from Burkina Faso are killed
and five others are injured when their convoy is attacked in the West African nation of Mali.
May 29, 2016 - Five UN peacekeepers are killed in an ambush in Mali.