Updated April 19, 2024, at 1:13 PM

Everyone remembers where they were on the morning of September 11, 2001. The tragic events of that day lead to the cancellation of sporting events, closure of national landmarks, and a three-day ground stop of all civilian aircraft in the US. Similar precautions were taken around the globe.

Thankfully, yet solemnly, we were soon returning to work and life slowly began to normalize. The airline industry made changes: only ticketed passengers in the terminal, no liquid containers larger than three ounces, and the cockpit door had to remain closed and locked for the duration of the flight. Over time, we’ve come to accept this as the new normal.