sky

i was wondering what's the best source for photography? and suddenly i realized it should be sky.
it's always available (at the easiest way we can open the window and capture it), we can capture it any minute of the day and night, so many good objects for photography are in it or come from it (sun, moon, stars, clouds, snow, rain, birds, airplanes, etc. sometimes unpleasant things also come from it like bombs or sometimes brids may take a dump on our head but anyway we should look at the bright side!), it has a different color and light at any minute of the day and more important than others it's same in the whole world!