After a fire is out, you and your family may return and ask, "Why are there broken windows or doors?"  One of the most surprising properties of fire is how fast it travels.  Fire fighters, however, are well aware of this and try to reach your home and get to the fire as quickly as possible.  If no one is home, sometimes they need to do "forcible entry," breaking windows or doors to get inside.  You and your family may also ask, "Why are there holes in the roof?"  Fires produce smoke, hot gases, and temperatures well over 1,200 degrees Fahrenheit.  At times, it is necessary to provide ventilation by eliminating these products of combustion before fire fighters can enter a building to extinguish a fire.  It must be expedited to help reduce fire spread and often includes cutting holes into the roof.  In addition to ventilation, walls may be forcibly opened to find "hidden" fires.  This allows complete fire extinguishment.  After the fire is out, some of the damage may appear unnecessary.  However, without the use of these fire fighting techniques, your home may be totally destroyed by fire.