Crown Prince Haakon Magnus and Crown Princess Mette-Marit arrive to attend the memorial service in the Government Quarter in Oslo, on 22 July 2011, ten years after a right-wing extremist killed 77 people in twin attacks. - Norway was plunged into horror on July 22, 2011, when right-wing extremist Anders Behring Breivik killed dozens in a bomb attack in central Oslo and a shooting spree on the island of Utoya.