Never forget.
I remember that eery sound. For me, the sound of bodies dropping defined the day.
They’re called PASS device, Personal Alert Safety System. If a firefighter stops moving for a set period of time (usually 15-30 seconds), they start beeping - loud, continuous beeping. It keeps beeping until the battery dies, or it’s turned off.
It’s to help locate a downed firefighter in a building full of smoke, flames. Hard to do under unnumbered tons of rubble, unfortunately.
The 9th anniversary is coming up - and it’s one I’ll always remember, if only because I got married on 7 July 2001. Sort of like getting married around Halloween 1941.