Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Ever since Neanderthal times people have lived together in groups. They would roam around foraging for this and foraging for that. Then they started settling down in one place and created villages, towns and now the cities we have today.
But a city is not just a collection of buildings. With the number of people living in cities numbering in the millions they cannot singly take care of themselves.
Modern cities have a supporting structure to be able to handle such a large number of people. This infrastructure is both visible, eg. bus and train networks and invisible, eg, water and sewerage. Without these important networks in place or if they are inadequate then the city comes to a standstill and is very smelly to boot
With a good infrastructure then city commerce is profitable, the city is clean and the users of that city, Mr. and Mrs Genpop, are very happy. The city becomes more and more popular and people start moving towards that city.