United Nations Secretary General Ban Ki-moon, right, walks along a barbed-wire fence assisted by former Auschwitz prisoner Marian Turski as he visits the former German Nazi Death Camp Auschwitz-Birkenau, in Oswiecim, Poland, Monday, Nov. 18, 2013. Ban Ki-moon will attend on Tuesday the U.N. Climate Conference held in Warsaw. (AP Photo/Alik Keplicz)