"Maybe four people will knock on my door a week asking if I have space or if I know of somewhere," butcher Ochieng, 26, said at the home he rents with his wife and four children.

Every day, new arrivals heave carts loaded with bags into Kibera before carrying their belongings across trenches of sewage and past mountains of garbage.

Once settled, many lack electricity, pay for water by the bucket and use over-flowing holes for toilets.

Slums like Kibera are the ugly face of urbanisation in Africa whose cities are increasingly overwhelmed by property crises, crime, over-population and creaking infrastructure.

"In the 1970s, Nairobi was truly the green city in the sun. It was safe to go for walks, there were no haphazard kiosks, no potholes," said a bookshop owner who gave his name as Chan. "Now the population has increased and infrastructure is strained."

International planners will come together next week in Nairobi for a five-day "Africities" summit to seek solutions to the problems caused by swelling populations in the continent's capitals.

Flows of rural people have strained resources for years. While some major cities have seen this migration stabilise, many remain burdened by the flow of people abandoning traditional subsistence farming due to conflict, environmental degradation and the breakdown of family structures devastated by AIDS.

According to the United Nations, sub-Saharan Africa, where 72 percent of the urban population lives in slums, has the highest rate of annual urban growth in the world.

By 2030, more than half of Africans will live in cities, making up a larger population than the whole of Europe.

"NO ONE CAN BE PROUD"

Lagos estimates its population at about 17 million, making it Africa's largest city. Its population is growing at 6 percent to 8 percent per year, or about 600,000 more people every year, attracting migrants from across Nigeria and West Africa.

But the sordid realities of city life make a mockery of official labels like "land of aquatic splendour".

The whole city has only 67 operating garbage trucks.

Police or gangsters demanding bribes man checkpoints and sights of dead bodies being dumped in public are frequent. Millions of Nigerians cook on firewood, collect water in buckets and spend nights in darkness.

About two-thirds of the city's residents live in poverty in more than 100 slums while housing for the rich has failed to keep pace with demand. Foreign executives can pay US$60,000 a year or more for a three-bedroom flat in the city centre.

Algiers, capital of relatively rich oil producer Algeria, also lacks space. More than 3 million people and 1 million vehicles are jammed into narrow alleyways and hillsides.

Years of conflict in the countryside have pushed millions into northern cities.

"No one can be proud of Algiers," said Interior Minister Noureddine Yazid Zerhouni, lamenting the decline of a city whose white-washed hillside buildings still retain -- if only from afar -- a fading picture-postcard charm.

"Problems of water, dirt, transport, insecurity. ... With all of that you can't rate it as one of the world capitals."

But there is money to seek solutions. Foreign firms have signed deals to build a tramway and Algiers' first metroline.

Angola's capital Luanda, built to accommodate 400,000 people, has become home to up to 5 million after many moved there because of a 27-year civil war that ended in 2002.

"In Luanda, very few people have gone back (to rural areas) and I think very few will," architect Allan Cain said. "Every year they spend in the city, their roots grow deeper." (Additional reporting by Wangui Kanina in Nairobi, William Maclean in Algiers, Tom Ashby in Lagos, Zoe Eisenstein in Luanda and Sarah McGregor in Johannesburg)