Both more than three million years old, the Australopithecus afarensis skeletons are on loan from Ethiopia, where they are considered national treasures. <br><br> Prime Minister Petr Fiala called the exhibition a “historic occasion,” while Ethiopia’s Tourism Minister Selamawit Kassa emphasized it was the first time the fossils have been shown together outside Addis Ababa. Discoverer Donald Johanson said the remains are a reminder that “we all share a common ancestry” in Africa.