The right answer is "An archeological dig finding fossil remains of Australopithecus Africanus in Europe and Asia". Homo erectus temporal range is, according to the Institute of Human Origins, 1.8 million to 50,000 years ago. The Australopithecus Africanus however was on our planet before that, 3 to 2 million years ago. So if a fossil specimen of Australopithecus Africanus was to be found in any place of Europe or Asia, the theory which assures that Homo erectus was the first hominid to leave Africa would then be invalid.
