There's something about the deep, inky blackness of a cave that sharpens the senses. And, sure enough, as our eyes adjust from the recently extinguished glow of the torch, tiny pinpricks of light appear. Glow worms. Deep beneath us, a faint trickling of water can be heard - an ancient creek gurgling its subterranean way through the limestone to the coast 4km away.
Simon Worsp, founder and operator of Adventure Waikato, turns on our helmet headlamps and explains that the cave we are standing in is millions of years old. Stalactites hang from the cave ceiling, vastly outnumbering the floor-dwelling stalagmites. They grow at the rate of 150 years per cubic centimetre.
This thrilling place is part of a 2.5km network of caves on the property, and an undisputed highlight. Jostling for attention, too, are the 220m flying fox across a gully more than 30m below, the abseil down a sheer rock face into a native bush-filled canyon, the Burma bridge and rope crossings spanning a stream and, refreshingly, the lack of tourist hordes. The place teems with wildlife - fantails, tui and kereru, and more rarely seen koura (freshwater crayfish) and cave weta.
During the 15 years Simon and his wife Rosie have been running the place, no one has ever been lost in the cave network. Though pushing your comfort levels is the idea, safety is paramount. And the choice is yours to overnight at the bunkrooms on site, or take it all in as a day trip from Auckland.
A la carte adventure: The Jurassic Stroll is the longest of the Adventure Waikato activities, taking four to five hours to complete at a leisurely pace. Alternatively you can embark on either a pure caving adventure or activities such as rock climbing, abseiling and the flying fox. Other choices include a muddy swamp crossing, archery and clay pigeon shooting. Excursions must be booked in advance, minimum of four people. Prices begin at $30, with the Jurassic Stroll at $115. Children as young as 7 can participate. For bookings phone (07) 825 4515.
Getting there: Adventure Waikato is 110km from Auckland, a drive time of around 1.5 hours. From there it is a further 55km to Raglan, via Waingaro Hot Springs - a great place to relax after all the excitement.