To celebrate a quarter of a century since German unification and the remarkably peaceful fall of the Berlin Wall, two brothers have this past week split the city anew. Only their border was made up of lights, 8,000 of them, spanning a 15km route that retraced the path of the original wall. "We wanted to counter this ominous, heavy structure with something light," says Marc Bauder, one of the artists behind the grand-scale art installation. The illuminated balloons were last night released, leaving only memories of their existence, but a keen YouTuber has gone to the trouble of taping their entire route.