Like Mangaia, Atiu has a cave--only a much larger one, and it has a mystery connected with the cave, which no one has yet attempted to solve.
Sixty years ago or more (I was told--I do not swear to the truth of this or any other island story that I have not had the opportunity of investigating in person), an invading tribe came to Atiu, and in the course of several battles, defeated and put to rout one of the lesser tribes of the island. The vanquished ones, fearing that they would be killed and eaten, plucked up courage to try a desperate expedient, and hid themselves in the cave, into whose dark recesses no native had ever before ventured, for fear of offending the evil spirits that were said to live therein. After waiting for a day or two, the enemies gave up the contest, and went away again. It was now safe for the hunted tribe to come forth, and the other inhabitants of the island looked to see them return--for after all, it did not seem likely that the evil spirits would destroy so many. They waited in vain. From the unknown depths of the cave--unknown, in its innermost recesses, to the present day--no sign, no message reached them; no living soul ever came forth of the many men, women, and children who had braved the dangers of that dark portal. Lost they were, lost they remained.
What happened to them? No one knows. It is not easy to destroy a whole tribe, and leave no sign. But the one white man who partly explored the cave some years ago, found nothing to hint at the nature of the tragedy. It is true that his candles gave out, and the cord that served him for a guide back among the endless windings of the place came to an end, so that he never knew quite how far the place went, or how many ramifications it had. Still, it is strange enough that not so much as a single human bone was to be seen. If the tribe had lost their way, and perished of hunger, some traces would certainly have been visible--a spear, a shell ornament, perhaps a skeleton. If they had fallen in a body over some treacherous inner precipice, the dangerous place would have been discoverable. Perhaps some new explorer will unravel the mystery, one of these days. It will not be a steamer passenger, however, for the Union boats on their rare calls do not stay long enough for any one to land, and the cave requires two clear days to reach and see.