The mosasaur is an extinct marine reptile that lived 70-65 million years ago. It had a long, barrel-shaped body, paddle-like flippers and a large heavy skull. It grew over 15 metres in length and weighed roughly 15 tons. In this image, a mosasaur is seen breaching the surface of the sea, perhaps in a desperate bid for food. An asteroid has impacted the Earth, throwing up a huge amount of debris and provoking a night that will last years to come. Acid rain is falling, destroying the gingko trees in the foreground.