Portrait of Lake Epecuén, its history and inhabitants. The medicinal qualities of its mineral waters. Its link with the Conquest of the Desert and the construction of the El Centinela fort during "the war against Indian domination." Pancho Francisco, Ranquel indigenous from the Calfucurá tribe and Catalina Costa, granddaughter of chief Manuel Grande, two centenarian survivors who became laborers of Mr. Nicanor Insúa's "La Monita" ranch. Carhué and the progress of the hamlet that became a city: its institutions and imposing buildings; its spas, hot springs and bathers, with special attention to women.