When American Airlines Flight 11 was hijacked on the morning of Sept. 11, 2001, a 31-year-old internet pioneer named Daniel Lewin did what his instincts had trained him to do. 

A former officer in Sayeret Matkal, the elite special forces unit of the Israel Defense Forces, Lewin reportedly stood up in the economy cabin to tackle the hijackers in front of him, unaware of another assailant seated directly behind. He was killed before the plane struck the North Tower, making him widely recognized as the very first victim of the 9/11 attacks.