In the early 1940s, the United States entered into an agreement with the Mexican government to create a temporary contract labor initiative. The Bracero Program was meant to address the labor shortage caused by World War II, but soon managed to bring its own specific set of problems. Hundreds of thousands of Mexican workers flooded towards the border and camped out at migratory stations where they waited before crossing into California. Laborers stayed at these stations from anywhere between a few days to months, often without money to buy food or a place to sleep. Even once a job in the US was found, conditions there were far less than ideal as bracero workers were often exploited by their employers.
Here is the audio and some pictures from the collaboration performance.