The plan to upgrade the United Nations complex at Turtle Bay involves putting a 35-story building on top of what is listed as a major terrorist target: the Queens Midtown Tunnel. That raised concerns that the tunnel would become an even more appealing target for terrorists, who might bomb the tunnel to collapse it, bringing down with it the U.N. building - perhaps while it housed the offices of the secretary-general and other high-profile U.N. figures during the renovation of the Secretariat. The proposed edifice is a 900,000-square-foot "swing space" that would accommodate Secretariat offices during the renovation of the...