Day of mourning declared in connection with the event, which led many lives (disaster, act of terrorism) or in memory of those events. In some countries declared mourning the death of current or former heads of state.
In the USSR national mourning was declared until after the death of Lenin, Stalin, Brezhnev, Andropov and Chernenko. The exception was in mourning over the death of the first cosmonaut Yuri Gagarin.
In the past year, Poland was declared a week of national mourning due to the death of President Lech Kaczynski and another 95 members of the Polish political and military elite.
Mourning for this occasion has been declared in several countries, including in Russia and Ukraine. In 2008, Kyrgyzstan mourning was declared in the day of the funeral of the writer Chingiz Aitmatov.
In Ukraine in recent years, national mourning was declared from the following reasons:
23 August 2006 — in connection with the crash of passenger Tu-154 near the village of Novgorod, Donetsk region,
October 16, 2007 — In connection with the tragedy, which occurred as a result of gas explosions in residential buildings of the city of Dnepropetrovsk,
November 20, 2007 — In connection with the tragedy that occurred in the city of Donetsk in the mine named after A. F.Zasyadki,
April 30, 2008 — due to the disasters of the Mi-8 in the vicinity of the platform, "Tauris" "Chornomornaftohaz" and the ship "Naftogaz-67" in the South China Sea,
December 26, 2008 — In connection with the tragedy in Yalta,
April 12, 2010 — mourning for the victims of the plane crash near Smolensk, the Polish president.
In Russia in recent years of national mourning was declared many times:
6-7 September 2004 — the loss of life during the terrorist attack on a school in Beslan,
5 May 2006 — about the plane crash over the Black Sea near Sochi,
July 10, 2006 — about the plane crash in Irkutsk,
August 24, 2006 — a plane crash in the Donetsk region of Ukraine,
21 March 2007 — an accident in the mine, a plane crash, a fire in a nursing home,
April 25, 2007 — mourning over the death of former Russian President Boris Yeltsin
August 13, 2008 — the humanitarian catastrophe in South Ossetia
December 9, 2008 — in connection with the death of the Patriarch of Moscow and All Russia Alexy II,
December 7, 2009 — in connection with a fire at a nightclub in Perm,
April 12, 2010 — mourning for the victims of the plane crash near Smolensk, the Polish president,
National mourning in Russia is usually declared when the number of victims exceeds 60 people.
In cases of terrorist attacks in Russia was proclaimed Local mourning:
30 March 2010 — in Moscow in connection with the attack on the Moscow metro stations "Lubyanka" and "Park Kultury"
January 26, 2011 — in Moscow and the Moscow region in connection with the explosion at the airport "Domodedovo".