Despite their fortifications, Spain's enclaves remain a tempting target for migrants desperate to reach Europe. The last two weeks have seen mass assaults on the border and many have been injured or even killed while attempting to scale the razor wire fences, as Chris Morris reports from the enclave of Melilla.
You can see them lurking in the shade of the trees - through the foliage, and through the razor wire which marks Europe's border with Africa. They are waiting for their time, for the chance to reach their promised land.
Migrants use gloves and cloth to protect hands against razor wire
Even among all the other places where rich and poor collide, this one stands out.
Melilla is an oddity - a tiny European enclave on the African continent. Part of Spain since the 16th Century, its faded colonial grandeur is protected by high fences and armed forces.
Every night a helicopter hovers overhead, another vain attempt to man the barricades of fortress Europe.
The migrants - young men from the war zones and poverty traps of sub-Saharan Africa - have one thing in their favour: strength in numbers.
Every so often, hundreds of them storm the fences, equipped only with makeshift ladders hewn from the branches of trees, and with cloths tied around their hands - to ease the pain of razor wire slicing through flesh.
Six young men were killed at the fence this week, some of them shot by Moroccan security forces on the other side of the border.
It's not necessarily the end of the journey for those who manage to cross
But many more than six made it across the frontier - and that makes the odds pretty good, they say, when you have risked your life over and again just to get this far.
Hasan is 25 years old, from Ghana. He's been travelling across Africa for three years to reach Europe's doorstep. Three years! These are strong people, with the determination to succeed.
Many of them leave their homes in West Africa as teenagers, with no clearer plan in their minds than to head north.
Everyone knows roughly where Europe is. They travel well worn routes up through the deserts of Algeria and Morocco - dangerous roads populated by smugglers, thieves and less-than-welcoming official receptions.
They all seem to know someone who hasn't made it - road accidents, fights, beatings have all taken their toll. But for the toughest, and perhaps the luckiest (although they don't always look that way once they get here) the instinct for survival and improvement is the driving force.
"I'm happy now I'm here," Hasan says, as he stands in a small crowd outside a holding centre run by the Red Cross on the Spanish side of the fence.
"I want to work, and I won't let them take me back."
He's been in Europe for 10 days, and he's dreaming of the job he'll find to help fund his family back home.
The Moroccan authorities have been accused of dumping migrants in the desert
But Spain may have other ideas. Hasan is another statistic, another illegal alien, and the authorities here have just sent migrants from third countries back to Morocco for the first time, under the terms of an agreement signed in 1992, but never before implemented by anyone.
Melilla, they say, has reached saturation point. It's the same story along the coast in Ceuta - Spain's other toe-hold on a continent it wants to keep at arms length.
A flood tide of illegal migrants has upset the cosy calculation that inequality can be sustained without cost.
It's happening all along Europe's southern frontiers. Here by land and elsewhere by sea they come - in rickety boats, barely fit to float and packed to the brim. To Malta, the Canaries and the Italian island of Lampedusa. In Malta even the army is outnumbered by illegal immigrants. And patience is wearing thin.
But, let's face it, this is the latter-day invasion we've brought upon ourselves. In a world of instant communications and global images we can't hide our affluence from anyone. The news has reached the smallest African village... and who can blame them if they start heading in our direction?
The response here? Well, the fence is being improved, going up in height from 10 to 20 feet. I can't imagine it will make much difference, the ladders will simply get longer.
But it does mark a toughening of official policy. It's a sticking plaster solution though, not a cure - and everybody knows it.
Nothing much will change until development brings more prosperity and more jobs to Africa - one of the great challenges of our times. This tiny land border feels a long way from Bob Geldof and Making Poverty History. But this I suppose is what that is all about.
For now we are left with the grainy pictures of the ladders being thrown against the fence, our modern version of the medieval siege. The bravest climb first, and take their leap into the unknown.
As darkness falls at Melilla's holding centre, small groups of migrants begin to queue for food.
Two plastic bags swirl in a sudden breeze and dance on the wind, as if in mock combat.
So many Europeans take what they have for granted. So many Africans are dying to get their share.
From Our Own Correspondent was broadcast on Saturday, 8 October, 2005 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.