Teniky's strangeness is precise rather than crude. Whoever worked this rock cut terraces into the slope, carved rectangular niches into the cliff faces, shaped boulders, and built stone walls arranged in a way that looks defensive - as if the place were meant to be held against attack. The Sahonafo River threads through the complex, past geological flourishes including a heart-shaped natural amphitheater. The best-known feature, the Grande Grotte in what researchers label Zone 8, has been documented since at least the late nineteenth century, when early observers reaching for an explanation dubbed it the "Grotte des Portugais," the Portuguese Cave. Nobody really knew. The name was a guess dressed as an answer, and it stuck for generations.

Modern science has begun to pin down the timeline. Radiocarbon dating of charcoal from man-made structures places their construction in the tenth to twelfth centuries CE. Shards of Chinese and Southeast Asian pottery scattered at the site date to the eleventh through fourteenth centuries - proof that the people here, despite their isolation deep inland, were plugged into the medieval Indian Ocean trade networks that linked Madagascar to ports across Asia. A team led by geologist Guido Schreurs of the University of Bern published their findings in 2024 in the journal Azania: Archaeological Research in Africa, drawing together excavation, dating, and the imported ceramics into the fullest account yet of who lived at Teniky and when.

The boldest claim concerns the cliff niches. The 2024 study found that their closest architectural parallels are not in Africa at all but in first-millennium Zoroastrian funerary niches in Iran, particularly the Fars region - the heartland of ancient Persia. From that resemblance comes a striking hypothesis: that Teniky may have been a necropolis, a city of the dead, built by settlers of Zoroastrian origin who carried their way of housing the dead across thousands of miles of ocean. It is a theory, openly framed as one. The researchers themselves propose comparing Teniky with contemporaneous sites in northern Madagascar - Mahilaka, Vohemar, Kingany, Nosy Mangabe - and a further expedition was planned to test the idea. The mystery is not solved. It has only become far more interesting.

Long before archaeologists arrived, the people of nearby Sahonafo kept their own accounts of Teniky, and these deserve their own respect. In one story, the Grande Grotte was home to a devouring ogre who lived there with his wife and their child, Tenika; when the child broke a water jug and fled in fear to a smaller cave, the family's calls in the dusk gave the place its name. Such malevolent beings populate Isalo's caves throughout Bara tradition. But another local memory is harder to dismiss: an elder named Tsimangataka recounted a "protohistorical" war between the people of the Isalo valley and long-robed strangers the Malagasy called Vazaha - foreigners - whose leader is said to have slept in the smaller cave. Foreign builders, robed and remembered as outsiders, a thousand years ago. The oral history and the Persian hypothesis, arrived at by utterly different routes, brush unsettlingly close.