They are the places where new economic ideas crystallize and where heterogeneous groupings of people learn to co-exist as neighbours. They are the places where new economic ideas crystallize, where heterogeneous groupings of people learn to co-exist as neighbours, and where democratic experiments emerge to make way for previously excluded social groups to be included as genuine decision-makers. The high density of people in cities facilitates economic growth through better sharing, matching and learning, and as Alfred Marshal famously ^ said, just the sheer concentration of people leads to new Ideas because “ideas are in the air." Not only do cities feature high densities of people, but their high densities also force people of different religions, nationalities, ethnicities and sexual orientations to live and work alongside one another, and in doing so, they get to know “the other,” leading to a cosmopolitan respect for differences. The 2008-2009 Occupy Wall Street protests across cities in the US were a collective uprising by low and middle-class groups to protest against their exclusion from the sharing of urban wealth.