The negatively charged bottom part of the storm sends out an invisible charge toward the ground. When the charge gets close to the ground, it is attracted by all the positively charged objects, and a channel develops. The subsequent electrical transfer in the channel is lightning.
As buildings become taller, lightning becomes more of a threat. Lightning can damage structures made of most materials (masonry, wood, concrete and steel) as the huge currents involved can heat materials to high temperature, causing a potential for fire.
Despite the adage, lightning frequently strikes twice. Tall buildings can receive dozens or even hundreds of lightning strikes over the course of a year, with multiple strikes possible during single storms. Without a lightning rod, each of these strikes could cause damage, electrocution or fires. Modern skyscrapers depend on lightning rods. Lower buildings and private homes also benefit from lightning rods, especially if the roof of the structure is the highest point in the surrounding area. With fire a likely result of even a single lightning strike, a lightning protection system is an effective way to divert the energy away from the structure safely.