Hip-hop artists from across the globe gathered at the World Urban Forum on Wednesday to spread a message to audiences that policy makers and politicians have failed to reach.
By Sara Sreberny-Mohammadi
It was billed a concert "for solidarity, peace and love".
Somali-born artist K'naan sang of his experience as a refugee
Acts from Greenland to South Africa performed in Barcelona as part of a United Nations campaign called The Message, which aims to raise aspirations among inner city children.
The Message hopes to reach 300 million young people who cannot go to school or find a job, involving musicians and youth groups in issues affecting the developing world's urban youth.
The open-air stage, with the cityscape on one side and the sea on the other, would have been a sell-out location for any big artist from Madonna to Robbie Williams.
Yet with the sun shining, the poor turnout was disappointing.
It was unclear what promotion had been done for the event - ironically, across the park itself in the city centre, there was a distinct lack of communication about The Message.
But the fans that did turn up were enthusiastic - a mixture of all ages and races - and genuinely pleased to be there.
A multi-ethnic Norwegian-based collective, Equicez, opened the show.
Godessa, from South Africa, were the only all-female group
They believed that as artists, it was their "obligation to inspire and educate".
K'naan, a Somali-born Canada-based artist, sang of his experience as a refugee and described the conflict in Somali as "justice being raped in his own home".
He also criticised misogynous lyrics in mainstream hip-hop, asking what happened to the "poor people's voice"?
Nuuk Posse - who brand themselves as Eskimo hip-hop - emerged from the previously unknown rap destination of Greenland.
Incorporating ancient chants and whale sounds, they surprised even the most hardened music enthusiasts with their innovative mixture.
Godessa, from South Africa, were the only all-female group out of the ten acts, while MV Bill from Brazil were first heard on the film soundtrack for City of God.
Still living in the infamous Rio favela, they fused Brazilian samba guitar and classical violin with an urban hip-hop sound to produce a vibrant and thoroughly enjoyable set.
Kenyan duo Gidi Gidi Maji Maji have already demonstrated the power of hip-hop in their own country.
They performed I'm Unblockable, the hit that became an anthem for democracy in the run-up to the Kenyan elections earlier this year.
Anna Tibaijuka, executive director of United Nations Human Settlements Programme, UN-Habitat, and Barcelona's mayor Joan Clos appeared on stage to thank the artists.
And Amos Kimunya, Kenyan minister of housing, told the crowd: "Together we can build a better world."