A year after the deadly attack, a group of Fresno firefighters decided to do 343 burpees for the 343 firefighters who never made it home that day.
The event is now open to the public.
Fresno Fire Captain Joella Garcia says the challenge is to make sure they never forget their sacrifice.
"We need to remember that this is a commitment to remember every year, we need to let our kids know what it is, we need to not forget what it is. And the reason for the burpees is to remember that we can feel pain every day," says Garcia.
All money raised from Saturday's event goes directly to the Fallen Firefighter Fund.