What to do with an empty city

I knew the square mile area of San Francisco is small: under 47 square miles. I didn't realize Manhattan is less than half that at 23 square miles (with a population of 1.5 million!). I knew Detroit is big -- I occasionally have to get to concerts on the other side -- and that it has the highest percentage of single family homes of any big American city. But a new map image is making the rounds of Detroit planning offices created by the University of Detroit Mercy and the Detroit Free Press. It shows Detroit and within its boundaries are both San Francisco and Manhattan -- with Boston thrown in for good measure and space left over. Boston is under 49 square miles while Detroit is almost 139 square miles. The point of all this: Detroit used to have 2 million residents. It has now less than 1 million, with most of the richest residents included in the exodus. The problem is the city has to maintain infrastructure for 2 million on a tax base of the poorest million. About 30% of the land is now vacant and huge numbers of houses are abandoned. A population this size -- even keeping the high percentage of single family homes -- could be put in an area much less than half of what the city must maintain now. Any ideas how to fix this? Good at selling your ideas? The job of mayor could be yours. But act fast, the primary is in February.