The North Tower (tower 1)
09/11/2001 8:45 am. American Airlines Flight 11 crashes into the North Tower of the World Trade Center, leaving a gaping hole, and a fire powered by jet fuel. At first, we thought this was just a horrible accident. We would soon be proven wrong.
(there aren't a lot of pictures of the first tower by itself. Most you can see the second plane coming in. But the only video of it crashing is available here)
Video of first airplane
Video of the North Tower collapsing
You need Windows Media Player to view the videos. You can download it fromHERE