People walk past a replica of a former East German BT 6 border watch tower at an exhibition about the fall of the Wall in 1989 in a shopping center at Potdamer Platz square in Berlin September 4, 2014. Berlin will mark the 25th anniversary of the fall of the Berlin Wall on November 9. REUTERS/Fabrizio Bensch (GERMANYPOLITICS - Tags: ANNIVERSARY SOCIETY) POLITICS)