We all know where we were and what we were doing on the morning of Sept. 11, 2001.
The first images stunned us, only to be followed by disbelief, anger and sadness.
For some Minnesota National Guard members, the horror was right in front of their eyes.
From this post in 2006 -- five years after the terrorist attacks -- Lt. Col. Steve O'Brien told the story of that morning.
O' Brien, the aircraft commander of C-130 flight crew from the Minnesota Air National Guard's 133rd Airlift Wing, remembers lifting off from Andrews Air Force Base -- admiring the sun shining off the Potomac River.
Then, he spotted an airplane at his 10 o'clock position. It was American Airlines Flight 77, which eventually crashed into the Pentagon.
In his words: "When I first saw the aircraft it was moving fast and that's when air traffic control called and asked, 'Do you see an airplane, can you tell me what kind it is,' and then asked for us to follow it. Never in 20 years of flying was I asked to follow a commercial airliner."
A few minutes later, O'Brien and his crew witnessed the nation under attack without realizing it: "We saw a fireball on the ground from jet fuel exploding and then saw the silhouette of the Pentagon through the haze of smoke."
As for what we saw, here's an incredible compilation of the network coverage of the attacks, via YouTube: