In fact, there were more peace walls now than there had ever been at the height of the Troubles. These towering structures maintained some degree of calm by physically separating the city’s populations, as if they were animals in a zoo. But the walls were still tagged with runelike slurs – K.A.T., for ‘Kill all Taigs,’ a derogatory term for Catholics, on one side; K.A.H., for ‘Kill all Huns,’ a reference to Protestants, on the other.