Pope Francis on Friday offered a private prayer at the former Nazi concentration and death camp at Auschwitz in Poland.He walked alone and in silence around the concentration and extermination camp in what was Nazi-occupied Poland where 1.1 million people, mostly Jews, were killed, BBC reported.Pope Francis also met elderly survivors of the notorious camp. After meeting them, he placed a candle at the Death Wall, where prisoners were executed by the Nazis.He is on his third day of a visit marking 1,050 years since Poland's adoption of Christianity, BBC noted.Francis has become the third Pope to walk through the main gate of Auschwitz, under its infamous inscription "Arbeit Macht Frei" -- work sets you free.