Eerie shapes emerge from the half-light as you descend into the Grotto. You make your way into the barge, which drifts off into a pitch black realm of absolute silence.

Suddenly, as you look upwards you realize the entire roof of the cavern is a mass of ghostly pale green twinkling lights, so densely packed together that it resembles the Milky Way galaxy.

The constellation of pinprick lights comes from thousands of glow-worms employing a chemical reaction to create their enchanting illuminations. The bright lights attract airborne cave dwellers lake gnats and minute flies, which become entangled in sticky threads.

Waitomo is a Maori word derived from ‘wai’ meaning water and ‘tomo,’ a shaft. The entire region is honeycombed with limestone caves, subterranean streams and deep ‘tomos.’ The caves are one of New Zealand’s most impressive natural wonders and have entertained visitors for over a hundred years. Both the Waitomo and Aranui caves have huge chambers containing delicate stalactite and stalagmite formations but the Waitomo Glow-Worm Grotto is the most popular attraction.

But Waitomo has much more to offer than the caves, having evolved into a top-class adventure tourism centre. Black-water rafting is all the rage here. Clients drift through pitch-black caves on underground rivers, lying on inflated inner tubes. ‘The Lost World’ is a free-hanging 100 metre abseil into an abyss, followed by an amazing caving experience as you crawl and squeeze your way out to the bright glare of daylight. ‘Haggas Honking Holes’ is a caving trip with four abseils, rock climbing and the challenge of negotiating waterfalls. ‘Cave Rafting’ involves a combination of abseiling, rock climbing and rafting – all in a subterranean stream.

Waitomo Village has a fascinating Museum of Caves and all the facilities of a holiday resort. From here you can drive out to the west coast via Marokopa and take in some dramatic above-ground scenic highlights. The Mangapohue Natural Bridge, 26 km west of Waitomo, has a giant limestone bridge formation and curious oversize rock oyster fossils. Marokopa Tunnel is a similar limestone phenomenon, as are the Piripiri Caves. Marokopa Falls are an impressive and photogenic sight.

For a truly other-worldly experience you can’t do better than come to this amazing karst country. It’s a labyrinthine netherworld that will delight and astound you as its secrets are revealed. Underground is where it’s at!