This week, the "Detroit Blight Removal Task Force Report" put some new numbers on America's biggest urban tragedy: 86,641 blighted properties, of which more than 40,000 structures are so far gone that demolition is the only option. The cost for this project: up to $2 billion.

As tens of thousands of people moved out of Detroit, and as Minneapolis and St. Paul have started growing again, the populations of these Midwest cities are reaching a rough parity of 700,000. The Twin Cities have also recognized how abandoned and boarded-up buildings can drag down a neighborhood, so each city posts lists of its "problem properties" as one way to inform the public and prod owners to do something about them. Assessing big fees is another one.

The most recent lists show 583 properties on the Minneapolis Vacant and Boarded Registry and 1,092 on St. Paul's Vacant Building List. Robert Humphrey, spokesman for St. Paul's Department of Safety and Inspections, explained to me that the larger number doesn't mean that his city has a bigger problem with vacant homes. Instead, St. Paul is quicker to include a property on its list, while Minneapolis generally waits until a vacant and boarded building becomes a real nuisance.

Those numbers have dropped substantially since the height of the foreclosure crisis, which ravaged poor neighborhoods in the Twin Cities and left hundreds of homes empty and rotting. The remaining vacant homes are concentrated in Wards 6 and 7, the eastern neighborhoods, in St. Paul, as well as Ward 1, and in Minneapolis, they're clustered in the two north Minneapolis wards, 4 and 5.

While Detroit's problems dwarf those of the Twin Cities, leaders in every city know those same trends are wreaking havoc on their own neighborhoods.

Every vacant structure tells a story about the changing city. That's why I'll be delving more deeply into the data in the weeks ahead.

Above: A vacant home awaits its fate in Minneapolis/Star Tribune file photo by Richard Sennott