It was presented by a delegation from interfaith organization, Earth Caravan. They were with Hiroshima survivor Setsuko Thurlow.
He told youth they can help other young people regain their enthusiasm.
It was part of Marie-Louise Coleiro Preca's final official meeting with the pope, before the end of her presidency.
The pope visited their prison in 2018. There he presided over a moving Holy Thursday ceremony.
