Lightning rod

Metal rod intended to protect a structure from a lightning strike

A lightning rod or lightning conductor (British English) is a metal rod mounted on a structure and intended to protect it from a lightning strike. If lightning hits the structure, it is most likely to strike the rod and be conducted to ground through a wire, rather than passing through the structure, where it could start a fire or cause electrocution. In technical documents, lightning rods are generally referred to as 'strike termination devices'.

From Wikipedia, under CC BY-SA. More on occurri.