Ball lightning has never been observed scientifically and many doubt its existence altogether. It is reported to occur with or right after a nearby lightning stroke and is described as a luminous ball of light that floats along fences, rooftops, or through the open air. The jury is still out on ball lightning. Lightning seems to strike some objects more than others. In New York, the Empire State Building is a favorite target.
Tall trees are also preferred.
In general, tall objects have a higher probability of being hit. In simple terms, the tall object brings the ground closer to the cloud. The leader, in seeking the easiest path, will naturally head for any piece of elevated ground. Having observed this tendency with his famous kite-flying experiments, Benjamin Franklin decided that he would mount a metal rod on the highest part of his roof. From the rod on the roof he ran a heavy wire to another metal rod that he had driven deep into the ground.