The young musicians all come from Cateura, a slum that's built upon a landfill; the 2500 families who live there survive by separating garbage for recycling. A 2010 UNICEF about this slum notes that more than 1500 tons of solid waste arrives each day. Illiteracy is rampant there, and Cateura's youngest inhabitants are often the ones responsible for collecting and reselling the garbage. The water supply is very dangerously polluted; on rainy days, the town floods with contaminated water. "A violin is worth more than a house here," says Favio Chavez, the orchestra's director and founder.

In the midst of such an existence, these musicians have created something both special and truly awe-inspiring. "My life would be worthless without music." says one girl in pigtails. A young man named Juan Manuel Chavez, nicknamed Bebi, has a cello fashioned out of an oil can and old cooking tools. For the camera, he plays the Prelude to Bach's Cello Suite No. 1 — beautifully.

"People realize that we shouldn't throw away trash carelessly," says Chavez at the end of the trailer. "Well, we shouldn't throw away people either."