Perhaps natural nuclear reactors operated in several other places on Earth two billion years ago. Perhaps we haven't yet found evidence of other natural nuclear reactors, or perhaps the radioactive remains of other natural nuclear reactors have long since been eroded or oxidized and dissolved. As of today, however, the Gabon natural nuclear reactors remain "unique, and certainly more irreplaceable, than the most valued specimens from the Moon and Mars." Since the Gabon reactors were so stable, operated over such a long time, and have been preserved for two billion years, scientific study of these unique natural reactors provides important insights relevant to anthropogenic nuclear power and nuclear waste storage. Mother Nature, it seems, knows how to operate a nuclear reactor.