In July 1936, the Spanish people resist the offensive by Franco’s army, backed by Italian and German fascists, aimed at conquering the country's major cities. Although many of the recruits to the new Republican Army are well trained, weapons and ammunition remain in short supply due to the non-intervention agreement initiated by France and signed by Italy and Germany. Yet the latter two countries continue to provide Franco’s army with military support and commit their troops on Spanish soil, while the fighters of the International Brigades return home.

El Socorro Rojo era una organización que canalizaba las ayudas que sindicatos, organizaciones obreras y partidos de izquierda de todo el mundo enviaban en apoyo a la República Española. Henri Cartier-Bresson documentó la tremenda labor de ayuda a la población civil que desarrollaba la organización, cargado de ilusión y esperanza en la causa republicana.