The aftermath of the scene of a nine alarm blaze.

The top floor could be seen through the collapsed roof.

Ladders rested against windows covered in ice at the scene of Wednesday's nine-alarm fire on Beacon Street in the Back Bay.

Needham firefighter Tommy O'Brien and his daughter, Peyton, 3, dropped off food at the firehouse on Boylston Street.

Flowers and notes were left outside the fire station.

Members of US Coast Guard had a moment of silence after dropping off a US Coast Guard flag.

Visitors and media lined up outside the fire station on Boylston Street.

A fire department official said authorities had no theory yet on the cause of the inferno that killed two firefighters.

Somerville firefighter Earl Johnson prayed in front of a makeshift memorial at Engine 33 on Boylston Street Thursday.

Lieutenant Edward Walsh (left) and firefighter Michael Kennedy were killed in the blaze.

Firefighters placed black bunting on the front of the Boylston Street station.

Erin Defuria, of Boston, was emotional after visiting the makeshift memorial.

A baseball cap with a written tribute to fallen firefighter Michael Kennedy was placed at the memorial.

Emergency medical technician David Stewart placed flowers in front of the station on Thursday.

Boston police officers paid their respects as a procession of firefighters moved toward the medical examiner’s office Wednesday night.

Firefighters escorted the body of one of the fallen firefighters from Boston Medical Center to the medical examiner’s office.

A moment of silence was held Wednesday night prior to the Celtics’ game at TD Garden to honor the fallen firefighters.

A man who said he was a firefighter placed flowers at a makeshift memorial in front of the Boylston Street firehouse.

Boston Fire Department Deputy Chief Joseph Finn, who was the incident commander at the scene, spoke to the media Wednesday.

Firefighters lined a railing at the scene to pay tribute to a fallen comrade; other firefighters continued to battle the blaze.

A composite image of two Boston Fire Department photos show firemen battling the blaze as fire shot from a window.