BBC Lagos aims to be Africa's model megacity By Egon Cossou Africa Business Report, BBC World News

Lagos is the financial heart of Nigeria, the most populous nation in Africa, and it is a teeming tangle of humanity and enterprise.

The economy of Lagos state is thought to be worth around $33bn, despite the chronic overcrowding, crumbling infrastructure and hellish traffic.

Expansion continues at a breakneck speed and part of the expansion plans for Lagos include an ambitious new city within a city. The Eko Atlantic project promises to turn Lagos into a hugely important financial powerhouse.

Under construction
Enormous quantities of rock are poured into the sea to build what is already being called the Great Wall of Lagos. A mile and a half out in the Atlantic Ocean, the city is taking a stand against the sea. Lagos is creating a seven-kilometre-long wall to hold back the waves.

For more than 100 years the sea has been eating away the shoreline of Victoria Island in Lagos – some ten metres disappear every year.

Now Lagos has what it hopes is a permanent solution to the problem of erosion. The idea is to claw back the lost land and build a new, futuristic city on it. It is to be called Eko Atlantic city. Every day some 90 trucks arrive weighed down by granite mined from the neighbouring city of Abeokuta and the wall is advancing some seven or eight metres a day.

Tackling overcrowding
Prince Adesegun Oniru, in charge of waterfront development, says the project was put together to protect Lagos because everything was gradually eroding away.

"Population growth within Lagos is always a problem," he says: "We have 18 million people that reside in Lagos state so you need projects like this to draw people away from the centre and spread them to areas like this."

Lagos is overpopulated and thousands more people flood into the city every month.

Rental prices for accommodation are some of the highest on the continent.

The new city within a city will offer residents constant power and water, good roads and a light rail system to whisk them around a financial centre reminiscent of Manhattan in New York. Four hundred thousand people will live and work in the new city, but first they will have to build it.

Engineering project
It is a big job to reverse, in just a few years, what nature has taken decades to do.

"You need some huge dredging vessels. The vessels we are employing are some of the largest in the world," says David Frame, the lead engineer on Eko Atlantic city project.

The giant dredgers from China pump 400,000 tons of sand a day into the space between the shore and the wall. Eko Atlantic city will need as much sand as the Palm One project in Dubai.

Lessons from Dubai
Prince Adesegun Oniru believes Lagos has much to learn from Dubai's troubles.

"The first lesson to learn as far as I am concerned is not to saturate the market," he says. "Finish a particular area completely and then move on to another – the moral is: don't saturate the market with too many properties."

A project this size has never been seen in West Africa before. Lagos has big ambitions to go with its big population. It wants to become Africa's model mega-city.