A lightning rod or lightning conductor is a metal rod or conductor mounted on top of a building and electrically connected to the ground through a wire, to protect the building in the event of lightning. If lightning strikes the building it will preferentially strike the rod, and be conducted harmlessly to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution. A lightning rod is a single component in a lightning protective system. In addition to rods placed at regular intervals on the highest portions of a structure, lightning protection system typically includes a rooftop network of conductors, multiple conductive paths from the roof to the ground, bonding connections to metallic objects within the structure and a grounding network. The rooftop lightning rod is a metal strip or rod, usually of copper or aluminum. Lightning protection systems are installed on structures, trees, monuments, bridges or water vessels to protect from lightning damage. Individual lightning rods are sometimes called finals or strike termination devises. The lightning rod was independently invented by Ben Franklin in the Americas in 1749.