Los Merinales Historical milestone · Dos Hermanas, Comarca Metropolitana de Sevilla, Seville Between 1940 and 1962 a concentration camp for Francoist political prisoners operated at Los Merinales, whose forced labor was used in building the Canal del Bajo Guadalquivir. 1940-1962 Photo: Cárdenas (CC BY 3.0) What to see and do in Dos Hermanas