In 1887, Māori chief Tane Tinorau and English surveyor Fred Mace descended into the Waitomo cave system carrying only candles and a raft. They floated beneath thousands of bioluminescent larvae — Arachnocampa luminosa — clinging to limestone overhead, each glowing to attract prey into sticky silk threads. The pair emerged hours later having documented what would become New Zealand's most visited underground attraction. Today the Waitomo Glowworm Caves receive more than half a million visitors annually, most arriving on day tours from Auckland that depart before dawn and return by evening. The cave system extends across 45 metres of depth, carved over 30 million years by subterranean rivers cutting through the Oligocene limestone of the King Country. Guided tours lead visitors through the upper dry chambers — the Banquet Chamber, where early 20th-century dignitaries held formal dinners beneath stalactites, and the Cathedral, a natural amphitheater with acoustics precise enough that Dame Kiri Te Kanawa performed there in 1997. The tour descends to the river level, where flat-bottomed boats carry groups in silence beneath the Glowworm Grotto. No photography is permitted; the larvae extinguish their glow under bright light, and the resulting darkness would leave twenty people stranded mid-river. Most Waitomo caves tour from Auckland packages bundle the caves with the Hobbiton Movie Set, 90 kilometres north, creating a circuit that covers both attractions in ten to twelve hours. The caves open daily from 09:00 to 17:00, with entry restricted to guided groups departing at 30-minute intervals. Standard adult admission is 61 NZD for the 45-minute underground tour, which includes the boat ride through the grotto. Peak crowding occurs between 10:30 and 14:30, when tour buses converge from Auckland, Hamilton, and Rotorua simultaneously. Arriving at the 09:00 opening reduces queue time from 40 minutes to under ten. The limestone formations grow at a rate of one cubic centimetre per century. The cave temperature holds steady at 12°C year-round, regardless of surface conditions. Rangers enforce a strict no-touch policy; human oils discolour the rock and disrupt the glowworms' breeding cycle, which peaks in the southern winter months of June through August when larvae populations double and the grotto ceiling resembles a densest star field visible from Earth.