The East Side Gallery in Berlin is a 1300 metre-long section of the Wall that was painted in 1990 by dozens of artist drunk on the ability to move freely about their city - and probably a considerable quantity of beer as well. It snakes along next to the river behind the Ostbahnhof train station. It has been so badly eroded by wind and rain and so often tagged by graffiti on the level of "Suzy Wuz Here" that the original art is scarcely visible in most places.
The bloke and I took a leisurely stroll past it. By the end, we had concluded that they'd gotten the philosophy of outdoor art completely wrong. Transience is intrinsic to graffiti. Attempting to preserve the original artwork on the wall was never going to work. Instead, we thought, a yearly competition should be held to repaint sections of the wall. Then it would be refreshed every year, an evolving symbol of the way Berliners (and all Germans) are adapting to unification.