A bomb was placed last month outside the visitors center just outside the Dale Mabry Gate at MacDill Air Force Base, Fla. Here, the visitors center is seen at the right of the gate, behind a sign greeting guests. (Luis Santana/Tampa Bay Times via TNS) (Tribune News Service) — For six days, a bomb sat at the doorstep of MacDill Air Force Base, the Florida home of U.S. Central Command.