evidence: Twenty-five years after the Good Friday peace agreement in Northern Ireland, Belfast still bears the scars of decades of sectarian violence. So-called peace walls are barriers built to keep Catholic and Protestant communities apart. NPR's Fatima Al-Kassab reports from the still-divided city. [...] AL-KASSAB: Carter Gibson (ph) and Crystal McCann (ph) grew up around the corner from each other on either side of the wall. Crystal lives on the predominantly Catholic side and Carter on the predominantly Protestant side. The teenagers say they would have never crossed paths if they hadn't joined this youth club. The peace wall still divides their communities. [...] AL-KASSAB: Paul Crawford's father was killed in the conflict known as the Troubles. He campaigns for victims' rights, and he lives in the predominantly Catholic west Belfast. He wants the walls to stay put as a sort of war memorial.