Though they are still rare , Americans speak of terror attacks at home . 1993 and 2001 : World Trade Center attacked ; second attack is cataclysmic . Obama calls bombings in Boston 'an act of terrorism ' LZ Granderson : April 15 , 2013 , serves as a deadly reminder . 2002 : Federal building in Oklahoma City bombed , claiming 168 lives . 2009 : In Fort Hood , Texas , 13 are killed in a hail of gunfire .
Though they are still rare , Americans speak of terror attacks at home . 1993 and 2001 : World Trade Center attacked ; second attack is cataclysmic . 2002 : Federal building in Oklahoma City bombed , claiming 168 lives . 2009 : In Fort Hood , Texas , 13 are killed in a hail of gunfire .