Most people don't think about what happens to their trash. Toss it into the bin and walk away. But there's a whole industry built around handling the detritus of society.

In the hygiene obsessed United States, trash is processed in clean factory settings. But even in the US, the people who do the work are at the bottom of the socioeconomic ladder, frequently immigrants.

In Mexico, where the workers are controlled by a mafia like syndicate, trash workers are also immigrants -- in Mexico City immigrants from the countryside, in southern Mexico, immigrants from Guatemala.

In Mae Sot, Thailand, the workers are undocumented immigrants from Burma.