JUST LAST month, on August 13th, ceremonies were held in Germany to mark the 50th anniversary of the building of the Berlin Wall. The wall lasted 28 years, until November 1989. Its fall heralded a new era in history as communist regimes in Europe fell, apartheid was swept away in South Africa and even the conflict in Northern Ireland suddenly seemed capable of resolution.
But walls remain in Northern Ireland, dividing its people, each one a testimony to political failure. The integrity of Northern Ireland's quarrel has seen to it that they have remained standing for 42 years now, since 1969 when the first went up in Belfast.
It is the sort of reality that can inspire despair of a type articulated by Winston Churchill in February 1922 when he remarked how "the whole map of Europe has been changed . . . but as the deluge subsides and the waters fall short we see the dreary steeples of Fermanagh and Tyrone emerging once again". The map of Europe has changed many times since then too, but the old rigidities remain intact in the North.
Even while unionists and nationalists share power in a devolved assembly, the physical divisions in Belfast and elsewhere in Northern Ireland still exist.
Many were built as temporary structures to separate Catholic and Protestant areas at the height of intercommunal violence in the early 1970s. They are still seen by residents as fulfilling an important function in keeping "warring factions" apart.
Some are over a kilometre long and six metres high. More modern ones, known as "environmental barriers", are less obtrusive. with brickwork or railings, trees and shrubs. But they divide communities just as effectively as corrugated iron and barbed wire.
One wall in north Belfast cuts through a public park, creating "Protestant trees" and "Catholic trees", as the Observer's Henry McDonald has noted.
In a report two years ago the chief executive of Northern Ireland's Community Relations Council (CRC) Duncan Morrow warned that without a fundamental rethink about these so-called peace walls/peace lines, mistakes made during years of conflict would be repeated.
CRC research disclosed in September 2009 that there were 88 peace walls/lines in Belfast, separating working-class loyalist from republican areas. It also found the majority were built after the ceasefires. In 1994 there was just 29.
Belfast is not the only place in Northern Ireland with such walls. The Northern Ireland Office, for instance, maintains five in Derry, five in Portadown and one in Lurgan. It maintains 42 in Belfast.
Some of these walls have become tourist attractions. An industry of "terror tours" has grown up around them in recent years. The sight of foreign visitors having their pictures taken beside Berlin Wall-style barriers made Duncan Morrow feel queasy.