It is projected that in the next 50 years two thirds of humanity will live in cities

Architecture critic Dejan Sudjic presents a four part series which looks at cutting edge solutions for transport and housing as well as ways of making cities cleaner and more liveable.

Part Four: Detroit

Once described as "the largest factory town ever built" Detroit is now a shadow of its former, industrial self.

Derelict factories and abandoned houses are a common sight in the city that has one of the highest unemployment rates in the United States and more vacant land than the whole of San Francisco.

All that is changing - the real estate market is thriving as one industrial building after another is converted into loft appartments for a new generation of urban dwellers.

From its own silicon valley to community gardening initiatives, Deyan Sudjic meets the people who are helping to reinvent Motor City.