BBC News Online's Joseph Winter has spent three weeks retracing the route of Mamadou Saliou "Billy" Diallo, a migrant from Guinea, who made it to Italy after a dangerous journey across the Sahara. Here, he reflects on his journey.
Travelling around West Africa, it really is astonishing how many young people have only one goal in life - to leave their home countries.
After five minutes haggling over the price of some headphones in the main market in the Senegalese capital, Dakar, Abdou the stall-holder asked: "Can you take me with you, when you go back to Europe?"
Four years passed before Billy could visit his wife in Dakar
Of course, such blunt requests rarely meet with success but it shows how desperate people are.
They are not necessarily the poorest people in the world - it is often the best educated Africans who want to leave, and who have the best chance of being welcomed in Europe.
They are exposed to Western adverts and they too want to be part of the consumer society, with the latest cars, television sets and clothes.
They know that they will not be able to afford such "luxuries" on the low wages on offer at home - if they are lucky enough to have a job.
But speaking to migrants at various stages of the journey, I was struck by how little they really knew before setting off about the hardships of the trip, especially overland, or the life of a migrant.
Billy left home in November 1999, thinking the journey would take just a week and he would be celebrating the millennium in Europe.
It took him six months.
Mohamed Dansakho has been on the road for eight years and is still in Morocco, trying to scale the barbed-wire fences to reach the Spanish enclave of Ceuta.
Once they leave - and tell all of their friends and family that they're going to get rich in Europe - it's extremely hard for them to go back home empty-handed.
An unknown number of migrants die each year trying to reach the "promised land."
I heard numerous credible stories about vehicles breaking down in the Sahara Desert and migrants dying of thirst.
Several people told me about migrants dying after being abandoned in the mountainous border area between Morocco and Algeria with no food or water, and others drowning while trying to cross the Mediterranean Sea.
Because the migrants are travelling illegally in remote areas, no-one knows how many die en route, but it is probably in the thousands.
And their families have no way of finding out what happened to them.
Many think that once they reach the "promised land" of the West, they will immediately become rich.
The truth is often very different - sharing a room with 15 other people and working in factories, stacking supermarket shelves or cleaning the streets.
Many of the Senegalese I met in Italy said they went hungry and rarely went out, in order to send as much money as possible to the family back home.
Mamadou Diallo from Guinea has spent many years trying to get to Europe. When he finally succeeded, and saw how other migrants were living, he went straight back home.
Mohamed has been on the road for eight years - he's still in Morocco
He says that if more people in Africa saw for themselves what the life of a migrant was really like, fewer would risk their lives trying to get to Europe.
The migrants are voting with their feet on the state of affairs at home and yet the exodus of so many active, and often skilled, young people does not help African countries catch up with Western living standards.
The World Bank estimates that 70,000 of Africa's most qualified people leave each year and the continent spends $4bn to replace them with expatriate workers.
It isn't just highly educated people leaving. Nigeria's President Olusegun Obasanjo recently said that food production was falling because so many farmers were fleeing the fields for the West.
But the money migrants send back home often supports huge extended families.
Billy and his brother, who is also in Italy, provide for about 20 relatives - their wives, children, aunts, uncles, parents and some cousins without jobs.
Few African countries have social security systems outside the extended family.
Many parents see raising the money to send one or more of their children to Europe as a way of ensuring that they will be looked after in their old age - the best possible pension plan.
Senegal earns 2% of its national income from remittances, Nigeria 4% and other countries even more.
While the huge disparity in living standards between much of Africa and much of Europe remains, people are going to want to leave
Worldwide, migrants in the West sent back $72.3bn to poor countries in 2001.
These figures ignore informal money transfers which probably count for two or three times as much.
Jean-Philippe Chauzy from the International Organization of Migration says it is very difficult to say whether the benefits of the remittances outweigh the problems caused by the departure of so many people.
While the huge disparity in living standards between much of Africa and much of Europe remains, people are going to want to leave.
"Migration is here to stay. It cannot be wished away," he says.
Europe in particular is trying to turn itself into a fortress to keep out what some see as the hordes massing at its borders, at places like Ceuta or trying to cross the 25km of sea which separates Morocco from Spain.
Only those who can prove that they are fleeing persecution or civil war are allowed to stay.
As a result, those people who have gone to Europe to look for work feel forced to lie, bogging down the immigration services in mountains of paperwork and investigations.
But Mr Chauzy points out that Europe's population is aging rapidly and young people are needed to work, and to contribute the taxes which pay the increasing number of pensions.
Most Africans live in poor rural areas
Europe's largest employer, the UK's National Health Service, has long been dependent on migrants to work as nurses and doctors.
The current situation satisfies neither Europe, where the tabloid headlines scream about "bogus asylum-seekers" or those in Africa who risk their lives trying to break through the fences.
Mr Chauzy says the solution is to have legal channels for would-be migrants to work in the West.
This, he says, would put the people-smuggling networks out of business and save the lives of the thousands who perish trying to seek a better life.
Aid agency Oxfam argues that another option would be to reduce subsidies to western farmers in sectors such as sugar, where there is direct competition with poor countries.
Most Africans live in rural areas and if living standards there were higher, fewer people would try to leave for the "greener pastures" of Europe.