Couple visiting the Waitomo Glowworm Caves in New Zealand

Photo: Donnie Ray Jones/Flickr

New Zealand is rich with amazing scenery and geological formations — from scorching geothermal springs to sweeping vistas worthy of fantasy epics. One of the most jaw-dropping destinations is the Waitomo Glowworm Caves, named for the thousands of bioluminescent insects that hunker down on the craggy walls within. Whether you take a guided boat tour or embark on a daring spelunking trip, this is one subterranean adventure you won't soon forget!

Located in the King Country region of North Island, these twinkling tunnels are just one part of the greater Waitomo Cave System, which also includes Ruakuri Cave and Aranui Cave.

The glowworm cave was first explored in 1887 by the local Maori Chief Tane Tinorau, who was accompanied by English surveyor Fred Mace. Although the indigenous Maori people knew about the caves long before this, Tinorau and Mace's expedition marked the first time the caves were thoroughly documented.

Equipped with an hand built flax raft and an arsenal of candles, the duo entered the dark, watery cave system, unsure of what they'd find. As their eyes began to adjust to the darkness, they noticed countless dots of light reflecting off the water. When they looked up to see the source of the light, they were greeted by thousands of brilliant, twinkling glowworms. Venturing further into the uncharted territory, they found amazing limestone formations, including stalagmites and stalactites that had been carved over millions of years by the cave's underwater stream.

After the initial spelunking expedition, Chief Tane and Mace went back many times to map out the tunnels and observe the unique wildlife. On one solo trip, the chief discovered an upper level of the cave with an easier entry point on land that would pave the way for more accessible (and less wet) exploration.
Arachnocampa luminosa larvae

Photo: mnolf/Wikimedia

The bioluminescent critters that grace the ceilings of this cave with their silk snares are Arachnocampa luminosa, a species of fungus gnat found only in New Zealand. Other names for this species include New Zealand glowworm, titiwai (which means "project over water" in the Maori language) or simply glowworms.

New Zealand glowworms spend between six and 12 months in the larval state, which accounts for the majority of their lifespan. Following the larval state, the insect spends only one to two weeks in the pupa stage and mere days in the final imago state as a winged, mosquito-sized insect whose sole purpose is to mate and lay eggs.

The species glows throughout most of its stages of metamorphosis, as a way to attract prey, find mates and, of course, illicit ooh's and aww's from adventurous humans!

Exploring Waitomo

Photo: Madeleine Holland/Flickr

In 1889, Chief Tane opened the cave to tourists who paid a small fee to be escorted through the caverns by the chief and his wife, Huti. After a few years of this arrangement, the government took over the administration of the cave in 1906 following the chief's death.

It stayed this way until 1989, when the caves and the land surrounding them were handed back to the descendants of Chief Tane. Today, his family receives a percentage of the attraction's revenue and maintains a strong voice in the cave's management and development.

Interested in taking a tour of this remarkable natural attraction? Visit the Waitomo Glowworm Caves website, which handles bookings for guided boat tours as well as a "Black Labyrinth" tour that features wet spelunking and black water tubing.

Water in Waitomo cave

Photo: Marcus Södervall/Flickr

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Catie Leary is a photo editor at Mother Nature Network. Follow her on Twitter and Google+.