Lightning formed when there is a potential difference between two sources. It can be from the clouds to the ground, or from the ground to the cloud and in all these pictures below, the lightning travels from clouds to clouds.
It is most amazing when one looks at the formation of the lightning, storm cloud laden with water, molecules rubbing with one another, thus building up the charges. The cloud banks behave like a giant capacitor till it can not hold the charges, and in a twinkling of an eye, the charges are released.
During the release, the surrounding air are superheated to temperature that is about 5 times the temperature on the surface of the sun! In this instance, the superheated air enters into the state of Plasma! (Usually we understood Liquid, Solid and Gaseous, but there is another state of matter which is called Plasma). In the plasma state, the air are highly ionised, and thus you can see the various colours of the ionisation of the air. Observed the colours surrounding the lightning strokes!
I took these pictures at home, with my camera pointing out of my window to the general direction of the lightning and adjust from there after each shot. It is impossible to frame or focus into the darkness, therefore manual setting must be done. All shots taken with 1/1.5 sec at F5.6. I did not hear any thunder, therefore these lightnings must be happening really far away. (Rule of thumb, when one see the lightning, one counts the second and stop when one hears the thunder, then multiply by 400 metres, that will give you the rough distance of the action).