In a sunlit clearing in central Gondwana, on an otherwise ordinary day in the late Cretaceous, the seeds of Earth's first and greatest civilization were sown in the grisly aftermath of a Tyrannosaurus' lunch. Throughout the universe, intelligence is a rare and fragile commodity - a fleeting glimmer in the long night of cosmic history. That Earth should harbour not just one but two intelligent species at the same time, defies the odds.