The practice of divination is one of the most distinctive features of Babylonian civilization and must be fully studied by any who would gain an appreciation of Babylonian thought. The Babylonian believed that the gods communicated their intentions to mankind by means of signs in natural phenomena and worldly events and that it was possible to learn to read these signs through prolonged observation and deep study. The absence of determinism here should be noted; the gods could change their minds at any time and often did so, but they would notify mankind of this. The vehicle of communication could be anything in earth or heaven and omens could be seen in the way smoke rose from a fire, abnormal births among humans or animals, the sudden appearance of a lion in a city street, an eclipse of the moon, or an unusual dream. The Babylonian was surrounded by ominous happenings.