An American flag flies over the rubble of the collapsed World Trade Center towers following the Sept. 11, 2001 terror attacks on New York and Washington.
That day, 10 years ago, made al Qaeda a feared and hated name in households across the United States.
The group, led by Osama bin Laden and at that time clearly based along the mountainous border shared by Pakistan and Afghanistan, enjoyed it's greatest success on Sept. 11, but it wouldn't be the last.
The coming decade would see al Qaeda adapt in deadly fashion to a much more overtly hostile environment, by changing tactics and locations. But as this collection of photos shows, their core philosophy of attacking civilians to instill fear has changed very little.