The Garin Death Ray
A good story, written by Alexei Tolstoy, the other Tolstoy's distant, poor relation;although extremely ideological, communist propaganda.
Why did I bring this up? In the story, when Garin sets up his mining operations, he brings in a multitude of workers of different ethnicities and races. They are all segregated from one another and inter-ethnic strife is encouraged as a way to prevent the workers from organizing and overcoming the people in charge.
The place where I am working right now is pretty unusual; at least I've never encountered this type of environment before. People seem to be hanging out purely with their ethnic groups - the Filipinos with other Filipinos, Indians with Indians, Russians with Russians, Chinese with Chinese. This always happens to some degree, but here it is very pronounced. Weird.