BERLIN, Germany — A bunker underneath the site of Adolf Hitler’s chancellery building in central Berlin could be lost to a new housing project, a heritage association warned Tuesday.The Berliner Unterwelten association, dedicated to preserving the city’s rich underground history, says that the bunker in question is one of four which have survived out of the many built by the Nazis in the district around the Brandenburg Gate.Covering an area of around 1,250 square metres (13,450 square feet), the bunker is “a historic site that absolutely must not be destroyed,” Dietmar Arnold, president of Berliner Unterwelten, told a press conference...