Where Are the Waitomo Glowworm Caves?

The Waitomo caves formed over 30 million years in Oligocene limestone, carved by underground rivers. Their most spectacular feature is the Arachnocampa luminosa — a gnat larva found only in New Zealand that produces blue-green bioluminescence. Thousands of these larvae hang silk threads from the cave ceiling and glow to attract prey (small flying insects drawn to the light become entangled in the sticky threads). Boat tours glide silently through the Glowworm Grotto, where the ceiling appears as a breathtaking "galaxy" of blue lights in total darkness. The caves were first explored by local Maori chief Tane Tinorau and English surveyor Fred Mace in 1887. Today about 500,000 tourists visit annually, carefully managed to protect the fragile ecosystem — CO2 from visitors breathing can raise cave temperatures and harm the glowworms.