From: Slate
… But before any of the horror unfolded that day, a little-known act of heroism is likely to have taken place on Flight 11 when Lewin—an Israeli-American who served in one of the most elite counterterrorism units of the Israel Defense Force (IDF)—rose from his seat and engaged in a struggle with one of the terrorists to try to thwart the hijacking. During the struggle Lewin was killed, making him the very first victim of the 9/11 attacks.