We have over 60 "peace walls" stretching over 20miles in Belfast.
Robert Frost parodies walls in a famous poem
", ‘Good fences make good neighbors.’
Spring is the mischief in me, and I wonder
If I could put a notion in his head:
‘Why do they make good neighbors? Isn’t it
Where there are cows? But here there are no cows.
Before I built a wall I’d ask to know
What I was walling in or walling out,"

The last line is the real question.