Anne Frank was one of the 1 million children killed in the Holocaust. In July 1942 Anne and her family had gone into hiding. Anne and her family went into hiding in an apartment which would eventually hide four Dutch Jews as well—Hermann, Auguste, and Peter van Pels, and Fritz Pfeffer.For two years, they lived in a secret attic apartment behind the office of the family-owned business at 263 Prinsengracht Street, which Anne referred to in her diary as the Secret Annex.On August 4, 1944, the Gestapo (German Secret State Police) discovered the hiding place after being tipped off by an anonymous Dutch caller.One month later, in September 1944, SS and police authorities placed the Franks, and the four others hiding with the Franks, on a train transport from Westerbork to Auschwitz, a concentration camp complex in German-occupied Poland. Selected for labor due to their youth, Anne and her sister, Margot were transferred to the Bergen-Belsen concentration camp near Celle, in northern Germany in late October 1944.After being betrayed to the Nazis, Anne, her family, and the others living with them were arrested and deported to Nazi concentration camps. In March of 1945, nine months after she was arrested, Anne Frank died of typhus at Bergen-Belsen. She was fifteen years old.Anne's mother, Edith died in Auschwitz in early January 1945. Only Anne's father, Otto, survived the war. Soviet forces liberated Otto at Auschwitz on January 27, 1945.