A thick layer of acrid, blue smoke hovers just above the waterfront slums that skirt Lagos lagoon, filtering out sunrise and sunset.
This man-made mist that clings to the rusted shack rooftops comes from the countless fish-smoking cabins that drive the slum economy.
There鈥檚 an uninterrupted view of the city鈥檚 dramatic sprawl of poverty from the road bridges that carry daily commuters between the islands and the mainland.
Fishing and sand-dredging boats drift to work, heading deep into the lagoon.
Many of the slums鈥 wooden huts are on stilts, others are just basic shacks shoddily built on the unstable ground of trodden-down rubbish dumps.
Nobody knows exactly how many people live in Lagos, but they all agree on one thing 鈥 Nigeria's biggest city is growing at a terrifying rate.
The UN says 14 million. The Lagos State government thinks it鈥檚 nearer 21 million, as rural Nigerians are drawn by the hope of a better life to one of Africa鈥檚 few mega-cities.
By 2050 Nigeria will have twice the population it has today, more than half will live in cities, and about 60% of them will be under 25.
In an overcrowded neighbourhood on mainland Lagos, Muktar Abdulhamid, 36, is pressing shirts with a heavy, old-fashioned iron filled with charcoals.
Abdulhamid is from a rural village in the northern state of Kano, and he鈥檚 left his wife and one-year-old child at home and come here to try to make money.
鈥淭his isn鈥檛 what I intended to be doing. I want to do business 鈥 to buy and sell,鈥 he says. 鈥淚t鈥檚 not easy to leave your wife, your child, it鈥檚 lonely, but I have no choice 鈥 it鈥檚 for the future of the family.鈥
There are few good jobs and housing is in high demand, but at least there are opportunities.
Every week tens of thousands of people arrive in Lagos, heading to neighbourhoods where friends and relatives have come before 鈥 many end up in the slums.
But Lagos State is planning tower blocks and transformation, reclaiming land from the sea for ambitious new developments.
In a rush to transform the city, the waterfront slums are being cleared, court rulings are being ignored, and luxury apartment blocks are springing up.
Can Lagos persuade wealthy investors to buy into a futuristic vision, while helping pull the poorest people out of poverty?
In about 30 years Nigeria will overtake the US to become the world鈥檚 third most populated country behind China and India.
It vies with South Africa for the status of the continent鈥檚 biggest economy, but it鈥檚 now in recession - beset by a drop in oil prices, and having to fund the fight against both Boko Haram Islamists and separatists targeting oil pipelines in the Niger Delta.
Like everywhere else in Africa trying to break out of poverty, Nigeria hopes fast population growth will bring it a 鈥渄emographic dividend鈥 鈥 a young workforce that can drive economic growth. If they can all be put to work.
Already there鈥檚 migration north to Libya and on to Europe, and the young who are left idle and without much hope are easily radicalised by Boko Haram.
It鈥檚 going to take great management, smart politics and increasing security and stability to turn rapid population growth into a positive and avoid the potential for disaster.
鈥淎frica鈥檚 Model Megacity鈥 flashes up in the glitzy video of beautiful sunsets and impressive artists' impressions of the big Lagos city development plan.
Soaring luxury skyscrapers sit alongside a port, enterprise parks and a new city-wide transport system of train lines, ferries and bus lanes.
But in the waterfront slums circling the lagoon, this vision is a threat to livelihoods, not a hope for the future.
Elebiomayo Folashade was a relatively well-off woman living in a sand-slum 鈥 but now she鈥檚 angry.
Pulling up her elegant blue dress, she leans down to inspect the damage done to one of her boats by security forces, and begins to cry.
鈥淭hey destroyed my boats and my husband鈥檚 boats and now I cannot pay the school fees, so the children have been withdrawn from school,鈥 she says. 鈥淚 am old 鈥 what am I going to do now?鈥
Many boats with huge holes in their hulls have been hauled up and abandoned on a beach that just a year ago was busy with work.
Ebute Ilaje is a place that has lived off sand-dredging for decades.
Wooden boats with food-sack sails would bring sand from deep in the lagoon to sell as building material, employing thousands of people.
But then the government 鈥渢askforce鈥 came 鈥 smashing holes in their boats and threatening to burn down the slum if they continued to work.
Now Folashade鈥檚 livelihood has gone 鈥 as has that of many in a community that depended on the sand-dredgers to keep the economy afloat.
Many believe what鈥檚 labelled a security crackdown against crime is an excuse to drive them out.
鈥淭he state government is interested in the land in all these waterfront communities... so the rich can benefit from it,鈥 says former dredger Oladipupo Aireomiye.
His fears stem from the recent clearance of Otodo Gbame slum, which went ahead despite a court order halting its destruction.
The bulldozers came in with the taskforce, smashing tin shacks, burning anything wooden to the ground.
鈥淭he police seized our documents and fired tear gas鈥 some people fled, others were shot,鈥 says Maxwell Hunga, who lived in Otodo Gbame.
鈥淭he most challenging thing we are facing is the threat of eviction that is hanging around the community鈥檚 neck,鈥 says Samuel Akinrolabu from the Nigerian Slum and Informal Settlement Federation.
鈥淥ver 40 communities are under the threat of eviction and 300,000 people would be rendered homeless eventually if this action is carried out,鈥 he says.
鈥淏ut forced eviction will not make slums disappear. Rather the moment you demolish a slum, naturally two or three more slums will spring up because people need somewhere to sleep."
They have the same fears in Ago Egun, the next slum along, where the men catch fish and the women smoke them on circular wire grills.
Their shacks are built on a floating rubbish dump - trodden down and compacted over the years, its paths wobble disconcertingly underfoot.
Klote Kakini is an old fisherman whose father lived here before him. He is worried his family will be evicted while he鈥檚 in the boat.
鈥淲hen we leave to catch fish, we are afraid something will happen to our wives and children at home,鈥 he says. 鈥淢aybe the government will send agents to demolish everything or scatter our families.鈥
But Steve Ayorinde, the Lagos State and governor鈥檚 spokesman, says these fears are unfounded: 鈥淭his is a government with a human face, this is a government that won鈥檛 just descend on helpless citizens and just bulldoze them away.鈥
He denies they have been heavy-handed by driving people from land they have lived on for many years.
鈥淚鈥檓 not aware that there has been any community that has been living within the waterfront for generations. It鈥檚 always a convenient lie for people to tell just to demonise the government,鈥 he says.
鈥淎ll over the world there will always be the need for regeneration of certain areas. It鈥檚 happened in New York, in London... and Lagos is not an exception.鈥
He gives two examples where people were resettled and compensation was paid.
鈥淥f course at some point there will be mild resistance, but this government believes in dialogue 鈥 in engaging with people so they can see the bigger picture of what the benefits would be.鈥
But Samuel Akinrolabu describes a different reality:
鈥淭he basic reason is land-grabbing, to be honest. Lagos government has seen that the waterfront communities are prime land where they can build the five-star hotels... and people can wake up and see the ocean view.鈥
He believes the answer to redevelopment is to leave people where they are, improve their lives in situ and create new space to house them.
"We are in an urban age and people are going to keep coming, so we are just going to have to find more creative ways to accommodate more people,鈥 says Taibat Lawanson, associate professor of urban and regional planning at the University of Lagos.
And they do keep coming - from other towns and cities, and from remote rural communities. Lagos has become Nigeria鈥檚 centre of gravity.
鈥淟agos has no choice but to go up,鈥 says Lateef Sholebo, head of Lagos State Urban Renewal Agency.
鈥淗ow are we going to accommodate all the population? There is no way we can continue to sprawl.鈥滱fter 25 years as a city planner in Los Angeles, he has now returned home to put into practice the lessons of urban renewal he has learned.
Emerging from the rusty tin rooftops and towering above the Eyo parade route is a multi-storey apartment block 鈥 a gleaming, modern show home rising from the slum.
鈥淭his project is very important because it shows the people in the community how a slum area can be transformed from what it used to be to a more modern, more sustainable environment,鈥 he says, enthusiastically.
Eleven families lived on the land 鈥 they were persuaded to combine their plots and stay elsewhere while the 48-flat tower block was built.
Now they have 11 modern apartments to move into 鈥 and 37 extra new homes for their neighbours.
鈥淭he air-space is useless 鈥 nobody is using it. Now we are able to go vertical we can reduce the overcrowding,鈥 says Sholebo.
鈥淚f we are able to convince all the rest of the families to participate in this kind of programme I think it鈥檚 better for them, it鈥檚 better for the government 鈥 and it鈥檚 better for everybody.鈥
But it took years to build and was hugely expensive - too expensive for the government to roll out across Lagos.
The city needs to be rebuilt without moving whole communities out.
That鈥檚 where Sholebo鈥檚 American experience could make the difference 鈥 using imaginative tax tricks to generate finance for the infrastructure to bring in private developers.
鈥淲e have to come up with different ways, or creative ways to provide such affordable housing,鈥 says Sholebo.
But those with the money to invest are looking for better returns elsewhere.
From the 11th-storey penthouse of the luxury Landmark Towers there鈥檚 an amazing view of the ocean and the sprawling waterfront developments.
鈥淲e are trying to create West Africa鈥檚 first one-stop shop, live, work and play destination,鈥 explains property developer Paul Onwuanibe.
The Landmark Group chief executive lives in the penthouse suite, and from the large, open terrace points out what will go where on the five-hectare, $100m development.
There鈥檚 already a Hard Rock Cafe, a fine dining restaurant, and an events centre which seats 4,000 people 鈥 hugely popular for expensive weddings.
Land has been cleared for a Marriott hotel, a small shopping mall, an IMAX cinema, two office blocks and two apartment buildings.
Here, people can avoid the Lagos chaos of overcrowding and terrible traffic congestion 鈥 the selling point is that if you can afford to live here, you never need to leave.
Onwuanibe鈥檚 five hectares are dwarfed by the massive Eko Atlantic project next door.
Earthmovers are landscaping this vast spur of land reclaimed from the sea, roads are being built and the first few tower blocks are beginning to take shape.
It鈥檚 a stark contrast from life in the slums 鈥 a symbol of the vast inequality in Lagos.
鈥淭here will always remain the super-rich and there will always remain the people just simply below the poverty line, but the hope is that over the next few years you will see that gap bridged as more people get more jobs,鈥 says Onwuanibe.
鈥淚 believe in trickle-down economics 鈥 so that wealth you create actually goes through the system, so the very people that feel that they鈥檙e displaced end up getting helped.鈥
鈥淲hen I arrived I thought it would be easy, but then I realised how much harder it was to get work, but you can鈥檛 just sit here without a job,鈥 says Muktar.
鈥淚 want to buy and sell, to have a shop in Kano and make enough money to go back to school to get a Western education.鈥
Many people in this particular Lagos neighbourhood are from northern Nigeria and speak the same language, and so it feels a little more like home.
But he misses the wife and young son he left behind nine months ago when he came to make it in the big city.
Back home in Yanoko it鈥檚 the rainy season - and bright green fields jump out from the stark background of burnt orange mud buildings.
There are only six cars, electricity is something they had for about a week before the new power lines fell dormant, and since the only bridge collapsed four years ago, it鈥檚 been even harder to reach the nearest health centre 27km away.
Seven thousand people live here - a two-hour ride on a rocky road from Kano, which is the biggest city in northern Nigeria.
Muktar Abdulhamid鈥檚 family are sitting together to talk about the man who left it all to make his fortune in the city.
鈥淲e don鈥檛 have money to eat, so we had to send the boy to go look for money,鈥 says his sister Ramatu Abdulkarim.
鈥淗e is getting a little bit every day, just enough to survive, thank God. Sometimes he sends us 40, 50, or 60,000 Naira,鈥 Muktar鈥檚 sister says.
That鈥檚 between $110 and $165 (拢85-拢125), equivalent to two months鈥 worth of the annual income the family makes from farming maize, rice, soya or chillies.
鈥淲e use the money for the farm and for buying food and clothing for the children 鈥 he also sent money for [his wife] Ramatu.
鈥淪he鈥檚 not comfortable that he鈥檚 not close to her. And he鈥檚 not happy that he鈥檚 far from her.鈥
Ramatu Muktar, 22, nods in agreement as one-year-old Abdulhamid plays on the floor 鈥 the whole family are praying Muktar will do well and take them both to Lagos to be with him.
She鈥檚 shy and says little, but Muktar鈥檚 good friend and cousin Saidu Yahaya says it鈥檚 all about having money 鈥 to improve life and plan for the unexpected.
鈥淭hey are making money there, but you know how things are, it鈥檚 meagre money. You have to manage the little you have for survival,鈥 says Saidu.
About 150 young men from Yanoko are also trying to get work in Lagos 鈥 and the road to town is only going to get busier.
鈥淟agos has always had that mixed blessing of having to deal with an influx of people. Unfortunately for us in the last two or three years it has been a deluge,鈥 says the Lagos State and Governor鈥檚 spokesman Steve Ayorinde.
He says 27 or 28 of the 36 states in Nigeria are struggling to pay local government salaries and it鈥檚 harder for people to migrate abroad.
鈥淲e want other people to be here 鈥 to bring ideas, to bring values, to bring innovation, but we鈥檙e just unable to deal with it endlessly,鈥 he says.
鈥淭he prosperity of Lagos, in a way, is also tied to how open it is... so visitors will always have a great role to play in Lagos if they play by the rules.鈥
More than half the population in Lagos is already under 25, and if there was work for them to do, and the birth rate was to slow down, the economy would get a welcome boost.
This is where the 鈥渄emographic dividend鈥 comes in - an opportunity to take advantage of a big and active workforce.
But if enough jobs aren鈥檛 created, the country suffers from the other side of that coin.
Too many unemployed young people provides a fertile recruiting ground for Islamists like Boko Haram or a market for the people-smugglers peddling dreams of wealth and a better life in Europe.
So if Africa's biggest challenge is everyone's problem, what's the solution?
The newly-trained staff in the glossy new Lagos factory are carefully packing phones into boxes.
As production lines go it's small, but for 鈥渢he first indigenous mobile, tablet, phone and computer assembly plant in Nigeria鈥, at least it's a start.
The company, Afrione, wants to tap into the big market for devices that a fast-growing young population provides, by producing cheap phones and tablets with the tagline 鈥淢ade in Nigeria鈥.
At the moment at least 90% of the components are imported, but company director Lekan Akinjide wants to steadily decrease that by 4 or 5% a year.
鈥淲hat we are actually doing fundamentally is starting the process - no-one else has really tried, no one else has really invested in a factory and the training of a skilled workforce,鈥 he says.
鈥淲e've looked at China, we've looked at India, we've also looked at what people have done here and tried not to make the mistakes they have made.鈥
China had a fast growing population. It had deep and pervasive poverty, it was a rural economy and it turned itself around in a generation, mainly through manufacturing.
But the window of time to take advantage of the 鈥渄emographic dividend鈥 is short 鈥 lots of jobs are needed now 鈥 and it鈥檚 perhaps worth looking a little closer to home.
There are some places in Africa where a new industrial revolution is seen as the key to putting the idle youth to work and cashing in on a growing population.
Ethiopia鈥檚 economy is dwarfed by that of Nigeria, but it鈥檚 the continent鈥檚 fastest growing and is betting it all on massive infrastructure investment and an industrial revolution to transform a nation of farmers into makers.
There are beautiful new six-lane highways, an electric railway line to the ocean, and vast estates of social housing are being built with government-run mortgage schemes to get the poor on the housing ladder.
And Nigeria knows massive investment in infrastructure is the answer to a growing economy and to get a congested city moving.
The population is even outgrowing the supply of electricity. Generators which fill the gaps are a constant background soundtrack to the city.
Stage one of Nigeria鈥檚 first electric railway line - through Lagos - is almost finished, but it can鈥檛 start moving a quarter of a million people a day from the suburbs to the city until its own power station is up and running.
鈥淭here鈥檚 a lot of new infrastructure being built, but it鈥檚 skewed and the effects are not felt by the common man,鈥 says planning expert Taibat Lawanson.
鈥淭here鈥檚 a gap between the rich and the poor.鈥
She believes by just improving transport links between residential suburbs and downtown, the government is missing the point 鈥 new satellite cities have to be planned and built so people can work near their homes and avoid commuting.
鈥淭he government has got to understand that people are going to keep coming.
鈥淭he current thinking is that they need to reverse urbanisation and get people to go back to the villages and stay away, but that鈥檚 not going to work.鈥
The luxury waterfront developer Paul Onwuanibe says inequality is everywhere, but he believes it's 鈥渁 little more acute, or visible鈥 in Lagos.
鈥淭hat鈥檚 just part and parcel of mega-cities, but one of the things the government would have to think of is some kind of social platform... some sort of welfare platform that catches people below a certain safety net.
鈥淎s this country and this city develops, you will see the gap bridged to some extent.
鈥淭here will be a lot of people that will always remain under the poverty line just because of the sheer numbers,鈥 he says, but believes the trickle-down from a growing economy and better private sector will see more people better off.
So what does Steve Ayorinde, the Lagos Governor and State spokesman, think the city will look like in 50 years?
鈥淭he pride of the black race,鈥 he answers quickly. 鈥淲here technology will drive practically everything.鈥
He talks about making Lagos a 鈥渟mart city鈥 - but millions of people living in slums just want better education and health, somewhere to live and somewhere to work.
鈥淛ust build modern houses for us - we are happy with where we are living,鈥 says Moses Sangoloke, a long-time resident of the threatened Ago Egun fishing slum, who chairs the community development association.
The government knows it needs to build. The people will keep coming. Lagos will keep growing.