When there is a strom we often see dark fast moving colud masses which make rumbling noise. The noise is generated by the lighting when it arcs across the sky. The electro static discharge in the atmosphere causes the lighting effect. It is very dangerous to be outside when there is a lighting strike.
Lighting bolts are mostly drawn by objects like lamp posts which are tall and are good conductors of electricity. Often tall buildings are deployed with lightning arrestors that help limit the effect of the lightning strikes. The cause of initial formation of lightning is still under debate. Lightning can also occur during volcanic eruptions in the ash clouds. Lighting aids in formation of nitric acid that is beneficial to plant life.
The study of lightning is called fulminology, and someone who studies lightning is called a fulminologist.
