Derry City has been named as a new member of the UN's International Cities of Peace Network (ICP), marking a commitment to peacebuilding.
The city received the award in recognition of its transition to peace following the Troubles in Northern Ireland.
Hundreds of young people from schools in Derry and Strabane gathered at Derry's historic Guildhall on Thursday, September 21 - United Nations International Day of Peace - to mark Derry's new status as a member of the ICP.
Mayor Patricia Logue signed an official declaration acknowledging Derry's commitment to peacebuilding at Thursday's event. Logue was joined by Reverend David Latimer, who first proposed the idea, and J. Frederick Arment, the founder of the ICP, who traveled from the US to attend the event.
Messages of hope and solidarity were broadcast from around the world as part of Thursday's event, including a message from the Reverend Canon Mpho Tutu van Furt, daughter of Archbishop Desmond Tutu.
"It's so joyful that Derry-Londonderry has been named a city of peace and we know that it will be a beacon of hope both now and in the future," Mpho Tutu van Furt said in a video message on Thursday.
A specially-designed Terrestrial Globe sculpture was also unveiled as part of the event. The sculpture was designed by Derry-based firm GES Campsie.
Speaking at Thursday's event, Logue said Derry's status as a member of the ICP represented the city's commitment to a peaceful future for all of its citizens.
"This is another important milestone in our journey towards securing lasting peace and a better future for everyone," Logue said on Thursday.
"It’s particularly fitting that this event takes place on the UN’s International Day of Peace, and also during Good Relations Week, a time to celebrate peace-building and cultural diversity across all communities. This year the theme is ‘Together’ and the importance of working together to achieve the common goals of equality, empathy and better understanding.
"By working with others from different backgrounds, but with shared hopes and ambitions, we can achieve so much more than working in isolation. This is where the true value in joining the International Cities of Peace lies."
Arment paid tribute to the young people of Derry and Strabane, stating that they gave the "entire world hope".
"Derry-Londonderry and the District of Strabane stand in the historical context as an inspiring case study of how a citizenry’s deep commitment to peacebuilding, reconciliation, and forward-thinking can bring hope to a world that yearns to be released from violence toward a vision of global peace," Arment said on Thursday.
Reverand Latimer said Derry's status as an ICP member was the "beginning of something", describing the network as a partnership of young people from across the world working together.
Students from each school in Derry and Strabane read out statements during Thursday's events and joined together for a choral performance of Phil Coulter's song "Brand-new Day".
The ICP comprises more than 400 communities in 73 countries across the world, spanning six continents.
Derry and Strabane became the first district on the island of Ireland to sign up to the ICP.