The second trend reflected a new interest in town planning, which brought together moralists, architects, engineers, and the urban authorities in a common project to create a center that could accommodate the new needs of the economy and society. They were driven both by fear and by ambition. The rapid rise in the population of cities like London, Paris, and Berlin created a spectre of unrest and social upheaval. The new industrial workforce, mostly living and working on the edge of the urban area, not only outnumbered the wealthier members of society, but had demonstrated its power in unrest across Europe from the end of the eighteenth century. Epidemic disease (bubonic plague from the Middle Ages until the early eighteenth century, and cholera for much of the nineteenth) was a constant worry, not only because of the high mortality levels during outbreaks, but also because of its capacity to spread throughout the urban area. In two successive days in July 1835, 210 and 173 cholera victims were buried in Marseilles alone.