Twenty-one firefighters died on December 22,1910, the most in the city's history.
Ringing a bell in honor of those killed in the line of duty is a tradition that dates back more than 150 years, according to the firefighter's union.
The widow of Chicago Firefighter Corey Ankum helped place a wreath at a wall memorializing those killed in the stockyard fire. Ankum and Edward Stringer died two years ago while fighting a fire on the South Side.
