Limestone caves on New Zealand's North Island whose ceilings glow with the larvae of Arachnocampa luminosa, a species found nowhere else. Thousands of blue points above an underground river look like a night sky; they are in fact lures for prey the larvae catch on sticky threads. Māori knew the caves long before Europeans, and the chief Tāne Tinorau led the first survey into them in 1887.

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Cahokia

The largest pre-Columbian city north of Mexico: at its height around 1100 it held perhaps twenty thousand people, more than London at the time. Monks Mound has a larger base than the Great Pyramid. Mound 72 contained a burial with over fifty young women laid out in rows, almost certainly sacrificed. By 1350 the city was empty, for no clear reason, and it has never been explained.