Helmut Kohl, the long-serving German leader who reunified his country after the fall of the Berlin Wall and championed Europe’s integration, died on Friday at 87. Kohl served as chancellor — first of West Germany and then of unified Germany — from 1982 until 1998, a 16-year term in office not seen since Bismarck. (Kohl’s one-time protegée, Angela Merkel, is now in her 12th year as chancellor.)