Vandals have been urged to stop targeting Ireland's only eternal peace flame.
The flame, at Londonderry's Peace Garden, went out last October but is back working again.
Vandalism and technical difficulties have caused problems since its installation in 2013.
Mayor of Derry Maoliosa McHugh said: "The feature is a symbol of hope and peace and is there to be enjoyed by everyone.
"Unfortunately, however, it has also been a regular target for vandals which has resulted in some damage to the flame over the years.
"I want to commend everyone who has worked so hard to restore it and take this opportunity to appeal to everyone to ensure that, in keeping with the spirit that it represents, the flame is now treated with the respect it deserves."
The Peace Flame was first brought to the city during Derry's UK City of Culture year as part of a global peace initiative by the World Peace Foundation, and was lit in the presence of Martin Luther King III in May 2013.
The campaign to have it introduced locally was led by Dr David Latimer from First Derry Presbyterian Church.
He said: "Difficulties associated with keeping our flame burning serve to remind us there is no magic formula to suddenly make all things new.
"Peace is a daily, a weekly, a monthly process gradually eroding old barriers and quietly building new structures."