In 2050, the world has changed in ways that would have seemed like science fiction only a few decades ago. Green spaces have spiralled skywards, interspersed with urban skyscrapers that breathe with the pattern of artificial intelligence. Cities glowed at night in a bioluminescent landscape, replacing street lights with shimmering pathways that changed colour according to the mood of the people walking by, thanks to state-of-the-art biofeedback technology.