Norway is commemorating one year since 77 people were killed and 242 were injured in gun and bomb attacks in Oslo and on the island of Utoeya.
Church services, a concert and other events are being held around Norway.
Most of the dead were teenagers attending a summer camp on Utoeyarun by the governing Labour Party.
The victims included eight people killed by a car bomb that went off in the capital Oslo.
Anders Behring Breivik, who has admitted carrying out the two attacks, remains on trial.
Breivik, who has been on trial for three months, has tried to justify the attacks by claiming he was trying to stop Muslims from taking over Norway.
But the BBC reports that the government, and much of the population, have actively promoted tolerance and openness to counter Breivik's views.
Judges are to announce next month whether Breivik is sane or insane, and therefore whether he will be given a long prison sentence or be sent to a secure psychiatric ward.