The old wine-making village of Heiligenstadt in the suburbs of Vienna has long been popular with visitors and locals alike. Its winding streets and pitched roofs give the place a rustic feel, especially in autumn when the leaves are turning and the vineyards are busy with grape pickers. Not surprisingly Beethoven came here on the advice of his doctor in the hope that some country living might improve his hearing.

But walk downhill from Heiligenstadt towards the Danube and the urban scene changes dramatically. Emerging like an island in the city is a very different sort of living space. This is the Karl Marx-Hof. Over one kilometre in length and spanning four tram stops, it holds the distinction of being the longest single residential building in the world.

The origins of this colossal structure can be found in the collapse of the Habsburg Empire at the end of the First World War. Out of this cataclysmic event, the First Republic of Austria was born — but the loss of so many former territories inevitably brought severe economic hardships, widespread unemployment and even famine.

Against this troubled backdrop, the vote was extended to all Viennese adults. That widening of the franchise, coupled with the rise of a powerful labour movement inspired by the country’s Marxist Workers’ Party, led to a landslide electoral victory for the Social Democrats. Vienna thus became one of the world’s first cities to be run by a firmly socialist government. In 1922, Vienna was made a separate Austrian federal province, distinct from conservative Lower Austria of which it had formerly been a part.