Come with me to Kiebera: the largest shantytown in sub-Saharan Africa. More than 500,000 people live in this vast illegal section of Nairobi, in mud huts on mud streets, with no fresh water or sanitation. Walk down Kiebera's sodden pathways and you will see a great deal of hunger, poverty and disease. But you'll also find health clinics, beauty salons, grocery stores, bars, restaurants, tailors, clothiers, churches, and schools. In the midst of squalor and open sewage, business is booming.

Indeed, Kiebera's underground economy is so vibrant that it has produced its own squatter millionaire, someone I have known for years. From his start a generation ago selling cigarettes and biscuits from the window of his hut, this Kenyan (he asked to remain unnamed) has assembled an empire that includes pharmacies, groceries, bars, beverage-distribution outlets, transportation and manufacturing firms, and even real estate.

Families flock to Kiebera for the same reason country folk have always migrated to the city in search of oppurtunity. In the city they find work but not a place to live. So they build illegally on land they don't own. There are a billion squatters in the world today, almost one in six people on the planet. And their numbers are on the rise. Current projections are that by 2030 there will be two billion squatters, and by 2050, three billion, better than one in three people on the planet. In itself, it is nothing to worry about, for squatting has long had a positive role in urban development. Many urban neighbourhoods in Europe and North America began as squatter outposts. London and Paris boasted huge swaths of mud and?stick homes, even during the glory years of the British and French monarchies. Squatters were a significant force in most U.S. cities too. It would no doubt surprise residents paying millions for co-op apartments on Manhatten's Upper east and West Sides to know that squatters occupied much of the turf under their buildings until the start of the 20th century. ............. from an article by Robert Neuwirth.