Watch FMovies. In the rich hill of Potosí in Bolivia there is a silver mine that was the largest in the world. It has been exploited since 1546 with the arrival of the Spanish who enslaved the indigenous people to steal the precious metal. To this day, hundreds of meters underground, the indigenous miners continue to exploit the mine in extremely precarious conditions, Martín Cádiz is one of them; hi works in the depths of the hill and desires that his children do not enter these tunnels of hell.