Few will forget the imagery from Sept. 11, 2001. That morning, 19 hijackers took control of four jetliners. Two were crashed into the twin towers of the World Trade Center in New York City, killing more than 2,600; another plane struck the Pentagon, where 125 died. The fourth plane didn't reach the terrorists' target, thanks to the bravery of passengers and crew members who fought to regain control of the plane; but it crashed in rural Pennsylvania, killing all aboard. In New York, in the immediate aftermath of the attacks, hospitals put their disaster plans into effect, preparing for mass casualties. Unfortunately, there wasn't much need for their services, since the death toll dwarfed the number of injured. But the attacks brought to light vulnerabilities and shortcomings nationwide in disaster preparedness, especially in surge capacity, staffing readiness and supply stockpiling. One week after the Sept. 11 attacks, the mailing of anthrax spores to offices of two senators and several news organizations killed five people and infected more than a dozen others. The attacks exposed additional public safety vulnerabilities—to bioterrorism. In Congress, these attacks spurred enactment of the Homeland Security Act of 2002, creating the Homeland Security Department.