A dream is a succession of images, ideas, emotions, and sensations that usually occurs involuntarily in the mind during certain stages of sleep.
We know that the rear portion of our brain gets pretty active during Rapid eye movement sleep (REM sleep, REMS) sleep, when most dreaming occurs. Some think that it'* just the brain winding down for the night and that dreams are random and meaningless firings of the brain that we don't have when we're awake.
