When the Germans invaded Italy in September 1943, her family fled south to Florence, where they survived the Holocaust, under false identities, protected by some non-Jewish friends. In her hiding place, she set up a laboratory in a corner of their shared living space. During the Nazi occupation, Levi-Montalcini was in contact with the partisans of the Action Party. After the liberation of Florence in August 1944, she volunteered her medical expertise for the Allied health service. Her family returned to Turin in 1945.