Sangatte is a nice little community of 800 people near Calais, in North Western France. It is part of the Pas-de-Calais département. It also lies on the coast of the British Channel. However that itself would not have been enough to make it famous as it is throughout the United Kingdom and France.
The village is close to the entrance of Eurotunnel that links France and Kent. Also, England is seen by many people all over the world as an attractive place to live in ; it is rather prosperous, has known peace for fifty years, and seems to be free of xenophobia. The normal route to go there is by plane ; however, depending on the country you are from, getting an entrance visa or even paying the plane ticket is rather difficult. So they have to travel by other means, mostly by land.
Many of those people come from the recently war-torn Afghanistan. As such they cross Iran, Turkey, the Balkans, Italy, and France by car or hidden in trucks. They might get in trouble at one of the borders, but it is not that hard to get through them. So they finally arrive to Calais, hoping for only one thing - to cross the Channel. At this point, they are nothing ; in France we call them sans-papiers. They are not allowed to be where they are : they had no visa upon illegaly entering the country. However France can't or doesn't want to send them back to where they come from : they have no papers proving their country of origin, and being smart, they won't tell it to the police. Also, it is not good PR to send people in some random violent country. On the other end, it won't admit them as legal immigrants : being "soft" on immigration is not so well seen in France among a part of the voting masses.
The only legal things the migrant can do at this point is either to ask for political asylum, or to leave the country. The first he doesn't want : his demand for asylum is much more likely to be granted in England, that is where he wants to go, and once he has made a demand in France, he can't ever make another one in the UK - you can only make one demand in the European Union. So the would-be refugee tries to leave across the Channel. The problem is, crossing it is not very easy : swimming across it is hazardous, and being allowed onto the boats or into the trains that hourly go to Dover requires being in a legal situation. Thence they try to cross by other means : hiding in a truck that crosses on one of the boats, or breaking into the Eurotunnel trainstation and literally jumping onto one of the trains that goes through the tunnel.
Of course our migrant doesn't make it on the first attempt : some border guard found him in the truck, some police officer prevented him from breaking into the station. Of course, after being arrested, he is quickly freed - the government doesn't want to send him away to another country, and he didn't do anything deserving more than a few months in jail. So soon enough he is trying again to cross the Channel.
By himself, a single migrant is not so much of a probem. But he is not alone ; many other would-be refugees end up in the same situation, waiting in Calais to get to England. This is not very healthy, having a thousand people living in the streets of Calais, with no roof nor any other means of living. So the Red Cross, whose job is to help people, especially refugees, decides to open a camp for those migrating people. An empty building, left over from the construction of the Eurotunnel, is occupied.
A problem that was previously unseen is now visible. the presence of the camp has made the media, both French and English, aware of the issues with th treatment of the asylum seekers. Everyone can imagine what happens when the Sun lays its hands on a problem involving both illegal immigrants and the French. Also, this makes more migrants more aware of the possibility of getting through the Channel via Calais. Thousands are now staying for a few days in the camp, hoping to get across the straits. Of course, this also gives birth to a business of helping those people escape the people who are to contain them.
The British government protests to the French one about those refugees waiting to invade England ; Eurotunnel protests those refugees are hindering its operations ; but the French government doesn't act. Those that are forgotten anyway are the refugees, who sold all they had for the dream of going to a country not only prosperous, but also safe.
UPDATE : At the beginning of November, Nicolas Sarkozy, the French Ministre de l'intérieur, had the Sangatte refugee camp closed. With the asylum laws in the United Kingdom toughened up, perhaps the incentive to seek shelter in Great Britain rather than in France will be diminished, but it seems as likely that people will continue to try and cross the Channel. And, in preparing their attempts, stay shelterless in or near Calais for weeks or months ; a humanitarian problem in one of the wealthiest regions of the world.