Standing in front of the squalid exterior of the Tacheles building in the heart of Berlin's Mitte district, I pause to ponder the existential question posed on the building's side. "How long is now" the giant mural asks passers-by, while the severe, stylised face spray-painted below suggests the answer is anything but frivolous.
This ambiguous statement presents the perfect paradox. Not just because of the absence of a question mark, or the poignancy of its sentiment, which echoes this city's tumultuous present and past, but because it intentionally contradicts its location's character.
"Tacheles", in Yiddish, literally means to speak bluntly and directly, a characteristic for which the German people are well-known, but which this piece of vague German vandalism manages to evade. In doing so, however, it holds a mirror to society and thus, transcends vandalism to become art.
The dilapidated Tacheles warehouse, originally a Jewish-owned department store, then a Nazi prison, became an alternative artist's enclave after squatters occupied it the year after Berlin's reunification.
It now sits crumbling, vacated and condemned to destruction and redevelopment. Nevertheless, the spray-can artists and taggers still come to add their mark. The building's façade is drenched with layers of colour and decades of paint: a giant mural of art.
Like an enormous concrete Etch-a-Sketch where the slate hasn't quite been wiped clean before more squiggles were added, generations of street artists have sprayed picture over picture and tag over tag across the walls.
In the process, they have turned this disused relic of society into a fascinating open-air art gallery. Berlin could very well be the city of graffiti artist Banksy's imaginings. The city is so slathered with zesty layers of paint that at times it seems it is nothing more than a three-dimensional concrete canvas.
Although by no means legal, graffiti in Berlin is poorly policed. This is because Berlin's underground art scene is no longer the exclusive realm of the city's wayward youth and subversive scribblers.
Graffiti tours of Berlin are now a major attraction. Local councils, therefore, are less inclined to remove work and prosecute offenders. The authorities' tolerance of graffiti and the abundance of empty buildings abandoned following German reunification have combined to make Berlin the current Mecca for street artists. Spray-can wielding pilgrims flock here from all around the world.
You really have to admire the lengths and heights, to which these nocturnal stealth artists will go to draw a picture.
Perhaps it is not surprising that this liberal form of expression, available to anyone with a spray can, is so popular where for years freedom of expression was in short supply.
With the fall of the Berlin Wall, stifled German emotions literally exploded on to city walls.
A quick walk around the grungy Kreuzberg district will soon reveal that the possession of a spray-can and some heavy emotional baggage do not an artist make. Berlin's street art is not all art.
Incredibly though, the vast majority of fresco paintings are great. Some are truly brilliant.
The colour, vibrancy, wit, and optimism of the pieces illuminate this lively city in a way that sways even the most hardened graffiti hater.
And the fact that Berlin's insatiable appetite for this imaginative and deliberately non-conformist art arose in the wake of Nazism and Communism, is simply the icing on that painted cake.