what makes a cityWho would be in charge of making a new city?

I was reading some articles online about people and businesses going green. And I started wondering what would happen if there was a whole city built for this purpose. Then I started wondering about who makes cities and well, the list of what I started wondering about keeps going for a while.
So my question is; who makes cities? This isn't really something you ever hear about, new cities just don't crop up that often. But who would be the ones to make a new city? Where would you even go to school for something like this?

Thanks!
The only new city I can think of is Brasília, the capitol of Brazil.

The city was planned and developed in 1956 with Lúcio Costa as the principal urban planner and Oscar Niemeyer as the principal architect. On April 22 of 1960, it formally became Brazil's national capital. Viewed from above, the main portion of the city resembles an airplane or a butterfly. The city is commonly referred to as Capital Federal, or simply BSB. Residents of Brasília are knownwhat makes a city as brasilienses or candangos (the latter referring to those not born in the city, but migrated there when the city was established).

The city is a world reference for urban planning. Planning policies such as the locating of residential buildings around expansive urban areas,as well as building the city around large avenues and dividing it into sectors, have sparked a debate and reflection on life in big cities in the 20th century. The city's planned design included specific areas for almost everything, including accommodation, Hotel Sectors North and South. New areas are now being developed for hotels, such as the Hotels and Tourism Sector North, on the shore of Lake Paranoá.


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Major cities are often the result of three things: Major trade routes and ports (Like New York, Boston, or Cleveland), stem from a mega corporation (such as Seattle), or from natural mineral deposits (San Francisco). Major cities, in the early days, were founded because of their proximity to the ocean, wwhat makes a cityhere they could set up trading ports. People expanded to various locations in the country to find mineral deposits (such as oil, gold, or coal). Cities would develop around a location with these rich resources and eventually a community would result. The reason that there a "ghost towns" are because the natural resources which once caused people to move there ran out. The other thing I mentioned was when a mega corporation sets up shop in a certain area. The perfect example of this is Seattle, because microsoft, starbucks, and a few other companies were founded in the area. The jobs and wealth generated from the companies enticed people to move there.
Sometimes the government - town planners, etc.
In the UK some years back there was a "new town" program that built some from scratch, e.g. Milton Keynes.
In Brazil I believe they build a new capital city Brazilia in the middle of nowhere.
But generally they just evolve.