One of the largest fires in Boston’s history started on the evening of November 9th, 1872. Known as the, Great Boston Fire of 1872, it burned 65 acres of downtown Boston and took over 12 hours to contain. It took 20 minutes for someone to strike a call box at which point the fire was already out of control. John S. Damrell, Boston’s Fire Chief at the time of the fire, was credited with saving lives and property through his heroic leadership. If not for Damrell, it could have been much worse.
One reason the fire was hard to contain was because of the horse flu. The Boston Fire Department used horses to pull fire engines, ladder carts, and hose reels. Unfortunately, at the time of the fire, most horses in Boston were sick with the flu; equipment had to be moved by teams of men, delaying the arrival of equipment to the scene of the fire.
Take a look at the Boston Public Library's print archive of the Great Boston Fire of 1872. The images are impressive. For context, this map, details the extent of the fire.