"Never Forget" is NYPD's motto, and a powerful reminder of that is the Wall of Heroes at police headquarters in lower Manhattan.
Hundreds of names are inscribed on the memorial wall -- those who died while serving with New York's Finest.
Five of the officers died from illnesses in the last year that officials said were contracted as a result of rescue and recovery work on Sept. 11, 2001.
The sixth, Det. Fermin Archer, died at 48 as a result of injuries received in a vehicle accident while on duty.
Also honored with a brass plaque on the wall was Lt. Christopher Pupo, 40, of Rockland County.
The recent deaths bring to 57 the number of those who have died from illnesses attributed to work they did on 9/11, the NYPD said. In addition, 23 officers were killed in the World Trade Center attacks.
The ceremony took place after the final pieces of the spire topping 1 World Trade Center were installed, making the structure perhaps the tallest in the Western Hemisphere.
The installation served as a reminder of the NYPD's loss and the city's recovery from the attacks, Mayor Michael Bloomberg said at the police memorial event.
"Today, 1 World Trade Center has received its spire, downtown Manhattan is more alive, more resonant than before Sept. 11, and that is because of the officers we are adding [to the Wall of Heroes] today," Bloomberg said.