Those of you born post-2001 are accustomed to the strict air travel rules that forbid taking even water past security gates. However, airports were not always like that. Seventeen years ago, passengers were not only allowed to carry on board all liquids, but also “dangerous” items such as baseball bats, box cutters, darts, knitting needles, scissors, and even four-inch blades. That changed on September 11, 2001, when members of the Islamic extremist organization Al Qaeda used airplanes as weapons to carry out the deadliest terrorist attacks on American soil in U.S. history.