The most popular tour is the Glow-Worm Cave starting at the award-winning Visitor Centre: a 45-minute trip through catacombs that range from bending low to the 15m-high "Cathedral", with the acoustically near-perfect limestone cave where Dame Kiri Te Kanawa and the Vienna Boys' Choir, among others, have performed.
Groups then descend to the lower levels where Waitomo River runs underground and the damp provides ideal conditions for what most people come here to see: glow-worms.
But limestone caves are more than just hangouts for luminous insects. Natural formations of stalactites and stalagmites line most caves. The most beautiful are in the "Fairy Grotto" of Aranui Cave, where you may even rub shoulders with a giant cave weta.
Aranui could be the set for a sci-fi thriller: contorted forms suddenly appear from the darkness as the path twists through it, sometimes barely wide enough to pass, sometimes headroom closes in, forcing you to duck, then bursts abruptly into blackness.
The jewel in the crown of the King Country karst environment is Ruakuri (Maori for two dogs) Cave. When local iwi found the caves centuries ago, they were inhabited by a pack of wild dogs.
Chiefs were interred in these caves, and this part is closed off to visitors. But the rest is so vast that the tour takes the best part of two hours.
The entrance down a dimly lit spiral path is reminiscent of a Victorian theatre. A stone sits at the bottom, its once-smooth top worn ragged by a constant drip of water that illustrates the processes at work here, where visitors are urged to wash their hands in a cleansing ceremony.
Ruakuri has beautiful rock formations, underground streams and glow-worms. But for a sheer otherworldly experience, nothing beats drifting along the stream of the Waitomo Glow-Worm Cave. Twenty people stare in complete silence at tiny blue lights in a pitch black "sky". It might be underground, but it's out of this world.
Glow-worm biology
Glow-worms are what attract most visitors to Waitomo. Officially Arachnocampa luminosa, the glow-worm is the larvae of a mosquito-like insect. By mixing oxygen with waste from food (poo), it creates "bioluminescence", the fairy light that you see on the cave roof.
The light attracts insects, which are caught in sticky lines hanging from the larvae to be the next meal and further fuel for this magical illumination. It has nine months to flash its heavenly glow before turning into a pupa, then emerges as a flying insect for just a few days before expiring.
The Waitomo Caves comprise incredible rock formations, underground streams and glow-worms.
OTHER STUFF TO DO IN WAITOMO
A visit to the Waitomo region doesn't mean finding your inner hobbit and spending life underground. The area has many great dining and drinking experiences, farm visits and outstanding natural features.
Mangapohue natural bridge
A former massive cave system that collapsed leaving a 17m- high limestone arch over Mangapohue Stream has resulted in a truly breathtaking sight, just 25 minutes from Waitomo Village. It's easily accessible from the road via a five-minute walk along a boardwalk. Climb the steps to get a closer look at stalactite-like formations known as epitrophic speleotherms, or bio-karst. There are also fossils of enormous oysters that date back about 35 million years.
Marokopa Falls
The Marokopa River plunges 30m to form a spectacular cascade of water, even in relatively dry times, as when I visited, reached by an easy five-minute walk from the road. (30 minutes from Waitomo.)
Ruakuri Walk
Along well-formed paths and a boardwalk, this walk is a real eye-opener to the essence of the Waitomo region. A deep, forest-covered gorge is fed by the Waitomo River that passes through the impressive Ruakuri Natural Tunnel. At night glow-worms line the rock overhangs along the paths. (The walk - which is 10 minutes' drive from Waitomo Village - takes an hour.)
King Country Brewing Company
If you like your ales hoppy, your wheat beers wheaty or need a refreshingly dry cider after an energising walk, KCBC has it all. Brewing since October 2013, they already have a reputation for producing high-quality, flavoursome and refreshing brews. (Available from Waitomo General Store.)
Top 10 Holiday Park
Not just a place to rest your head in modern, well-equipped cabins or your own motorhome or tent, the park also has a pool for cooling off in in the King Country summer sun and a hot-tub that soothes aching limbs after long walks above and below ground.
Waitomo Visitor Centre
An incredible architectural triumph in its own right, the Visitor Centre has an informative display on the history of the area, both natural and human. It's also the place to book tours, buy souvenirs and catch your breath with a long black or lunch.
Alex Robertson was a guest of Discover Waitomo and the Waitomo Top 10 Holiday Park.
