Waitomo Glowworm Caves, Show cave in Waitomo, New Zealand

The Waitomo Glowworm Cave runs 1,300 m of passages on two levels, with two entrances 14 m apart vertically. From the top entrance, a 39 m main passage passes the 16 m shaft called the Tomo, and a 40 m passage leads to the Blanket Chamber. The lower level holds the Waitomo Stream in a series of lakes, and the Glowworm Grotto ceiling is covered with Arachnocampa luminosa larvae.

In 1887 Tane Tinorau and surveyor Fred Mace entered the cave by raft at the stream entrance, lighting candles; Tinorau later found the upper entrance used today. Tinorau and his wife Huti began guiding paying visitors in 1889. The government took over the cave in 1905 for £625 under the Scenery Preservation and Public Works Acts, and in 1989 the land and cave were returned to the original Māori owners, whose descendants share revenue and management under the 1990 Waitomo Deed of Settlement.

The name derives from Māori language, where 'wai' means water and 'tomo' means hole, reflecting formation through water erosion. The caves sit on land traditionally owned by Māori people, and descendants of chief Tane Tinorau have managed them for generations, maintaining a strong connection between the indigenous community and this natural site.

Access occurs through guided tours lasting approximately 45 minutes, which include walking through illuminated sections followed by silent boat rides in complete darkness to observe glowworms on ceilings. Photography is prohibited inside to protect larvae, and temperatures remain around 52 degrees Fahrenheit (11 degrees Celsius) year-round, so bringing warm clothing is advisable.

The Arachnocampa luminosa species creates silk threads from ceilings to catch prey, using bioluminescence as a natural hunting mechanism. Each larva can spend up to nine months in this luminescent stage before pupating, and individual threads can contain dozens of sticky droplets that trap unsuspecting insects attracted to the blue-green light produced by chemical reactions within their bodies.