Back at its mid-20th Century peak - before the race riots, before white flight, before the decline and fall of General Motors - Detroit had a population of close to 2 million. Since then it's shed more than half its population and now, according to City Farmer, "about 30% of Detroit is now vacant land — about 40 square miles, by one estimate." Forty square miles is roughly the size of San Francisco.
You can see the change in the city in these maps of population density from Wayne State's Center for Urban Studies:
For a concrete illustration of the effect of this diminution on the urban fabric, here's a Google maps image of a neighborhood in central Detroit:
This smattering of houses amidst vacant lots looks positively pastoral, but it's within walking distance of the old Tiger Stadium as well as the once-illustrious Michigan Central Station (pictured below). Places like this are common around Detroit
So what can be done to save a city that seems to be evaporating away? The Telegraph discusses one approach that might make sense:
The government looking at expanding a pioneering scheme in Flint, one of the poorest US cities, which involves razing entire districts and returning the land to nature.The problem is that economic growth in the US over the past several decades has largely been driven by urban development (for which read: suburban sprawl). In some ways, the old manufacturing base of the economy has been replaced by construction - of housing, strip malls, glass office boxes - and associated financial activities (a model for growth that met a bit of a notorious end in the last few years (at least one hopes it was an end)). As short-sighted as such a growth model might have been, its legacy - as well as the legacy of the history of a country that has grown from a few towns dotting the East Coast to a continental empire with the world's third-largest population - is that contraction seems synonymous, in the American context, with defeat. As Kildee says: "The obsession with growth is sadly a very American thing. Across the US, there's an assumption that all development is good, that if communities are growing they are successful. If they're shrinking, they're failing."
Local politicians believe the city must contract by as much as 40 per cent, concentrating the dwindling population and local services into a more viable area.
The radical experiment is the brainchild of Dan Kildee, treasurer of Genesee County, which includes Flint.
Having outlined his strategy to Barack Obama during the election campaign, Mr Kildee has now been approached by the US government and a group of charities who want him to apply what he has learnt to the rest of the country.
Mr Kildee said he will concentrate on 50 cities, identified in a recent study by the Brookings Institution, an influential Washington think-tank, as potentially needing to shrink substantially to cope with their declining fortunes.
Most are former industrial cities in the "rust belt" of America's Mid-West and North East. They include Detroit, Philadelphia, Pittsburgh, Baltimore and Memphis.
In Detroit, shattered by the woes of the US car industry, there are already plans to split it into a collection of small urban centres separated from each other by countryside.
"The real question is not whether these cities shrink – we're all shrinking – but whether we let it happen in a destructive or sustainable way," said Mr Kildee. "Decline is a fact of life in Flint. Resisting it is like resisting gravity."
But changes in cities like Flint and Detroit don't have to follow a pattern of collapse. Kildee proposes another metaphor for the process of urban contraction in the Rust Belt:
Mr Kildee acknowledged that some fellow Americans considered his solution "defeatist" but he insisted it was "no more defeatist than pruning an overgrown tree so it can bear fruit again".For more, see this Google street view tour from James Howard Kunstler's podcast, as well as this site on the ruins of Detroit.