Ancient Australian Aboriginal mythology suggests the rain and cloud spirits would descend from the sky to paint Wandjina figures on the cave walls. Tradition mandates the reliefs to be repainted and refreshed by the current oldest living descendant, and it's believed this tradition has continued on since original prehistoric Aborigines. Oddly, the paintings seem to resemble alien faces, with large dark eyes and a rounded head. Outside of the head is a shape familiar in renaissance art, the halo, which appeared thousands of years later according to record.
It's also interesting to note a few of the Wondjina drawings demonstrate ascension, or an upward movement toward the heavens. Although interpretation tells us Wandjina represent rain spirits, there seems to be much more to this story. Wondjina believe that dream-time is cosmological time, the principal order of all things to exist in the universe. It's believed some versions of these paintings do not contain mouths otherwise it would continue to rain without relief. Maybe in those versions, mouths were omitted to mark silent moments, or the mouths themselves did not receive a new coat of paint at some point. Or, the lack of a mouth could have a significant meaning to Aborigines which we have yet to decipher.
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