Two hijacked commercial aircraft crashed into each of the World Trade Center twin towers in New York city, and another into the Pentagon building. On that day 3 building in New York, the twin towers and World Trade Center 7 all “pancaked” down onto their foundations, the latter was not hit by any aircraft! Chances?. [1]
This event triggered an enormous US effort to combat terrorism, a “threat” that from this point on, became real in the minds of the global community.
“The crises of 2001 led to a cultural shift in how public health, emergency management, and medical experts think about national security….Health departments became accepted as important partners by traditional emergency management.” [2]