This work presents a short-documentary about a geochemical research accomplished on the Castilseras reservoir,
located in the Almadén mining district (Ciudad Real, Spain). As results of the work a documentary of 15 minutes length has been realized; in this documental the authors present in a simple and didactic way a brief history of the mining district, the problematic associated to Hg and a real case of geochemical study accomplished on the reservoir. The short-documentary could be used as a useful tool for the visual llustration of geochemical surveying guidelines in practical and theoretical lectures for students.
