After the 1994 genocide in Rwanda, world leaders said they'd never let it happen again. But another humanitarian disaster is taking shape in Rwanda's neighbor. The Democratic Republic of Congo, a country the size of Western Europe, is rich in minerals but desperately poor in infrastructure. More than a million people are already displaced, and 250,000 civilians have fled their homes during weeks of violence. Government forces, rebels, rival tribes and UN peace-keepers all are part of the story. The Financial Times' Matthew Green is in Goma in the eastern part of the country.