A fire hydrant is a visible connection point for firemen to tap into a water supply that is installed in predetermined areas. Fire hydrants with connections to a water service network must be installed in all buildings, parking lots, roadsides, mines, and industrial zones, among other places. They're made to supply firefighters with the water they need to attack and extinguish a fire quickly. Underground fire hydrants were used until the 18th century. Above-ground pillar-type fire hydrants became popular and widely employed from the 19th century onwards. A fire hydrant is just a pipe with a valve that allows water to flow from a water main to extinguish a fire