Several hundred peace campaigners have formed a human chain around Belfast City Hall in response to the street violence over flags.
They linked arms and prayed for five minutes during the vigil.
A number of church leaders were among those taking part.
Organiser Andrew Masters said the event sent out a powerful message that people in Northern Ireland supported peace.
He said: "We feel that this year has been in many ways incredibly positive through the 'Our Time Our Place' (tourist board campaign). But, what the past 10 days have shown us is that we have come so far we still have quite a journey ahead of us.
"We just wanted to stand and pray for hope and peace."
Loyalists have staged protests across Northern Ireland since December 3 when councillors in Belfast voted to reduce the number of days the Union flag is flown over the city hall.
Disorder has erupted at a number of the pickets and almost 30 police officers have been injured during the trouble.
East Belfast Alliance Party MP Naomi Long received a death threat from loyalists, while senior Democratic Unionists Jeffrey Donaldson and Edwin Poots have also been informed of threats, apparently from dissident republicans, after speaking out in favour of flying the flag.
A number of councillors from the cross community Alliance Party have been advised by police not to return to their homes.