In the depths of Ruakuri Cave, I'm surrounded by a smorgasbord of golden rock formations.

"It's like lasagne," someone exclaims as we peer at intricate ripples of thin, cream coloured rock, hanging vertically from the sides of the cave.

"Or cauliflower," says someone else, inspecting a knobbly stalagmite teetering beside the path.

All around, a steady, tuneful dripping tinkers off the undulating rock faces. The air is cool and tinged with a crisp dampness on which our voices float softly away. We hear our words bounce through dark tunnels and crevices before reverberating along the softly lit path back to where we stand.

Ruakuri is just one of around 300 known limestone caves that lurk beneath the hilly, verdant land of the King Country region in the central North Island. With a resident population of just 52, the sleepy township of Waitomo welcomes an astounding 600,000 visitors a year, all angling to float, climb, cruise or wander amongst the world famous Waitomo Caves.

Having already hurtled along a cave stream on a floating inner-tube, I'm now enjoying the more sedate exploration of Ruakuri Cave - Waitomo's longest underground walking tour. The two hour adventure follows the 1.6 kilometre underground tunnel that spirals down into Ruakuri's depths and weaves its way through the cave's innards.

"Thirty million years ago this was all under the sea," says our guide as our small group shuffles along the path, staring in awe at the perfect clusters of stalactites and the intricate grooves of the cave walls.

The limestone was created by layers of dead marine creatures on the sea floor. When earthquakes and volcanic eruptions forced the sea floor upwards, the limestone emerged, buckling and braking as it came. Water flowed between the enormous cracks and joints and, over time, carved out the caves that we're walking through today.

The name 'Waitomo', given by early Maori settlers, is a perfect description of this region's geological landscape. 'Wai' is Maori for 'water'; 'tomo' means 'entrance' or 'hole'. Full English translation is said to be 'the stream which flows into the hole in the ground'.

'Ruakuri' is another Maori name, which translates to 'den of dogs' - a reference to the pack of wild dogs that were living in the cave's entrance when it was discovered 500 years ago. Maori chief Tane Tinorau brought his people to live near the cave. They used the cave entrance as a burial ground, making it a sacred and spiritual place.

In 1904, Ruakuri was opened as a successful visitor attraction. It was eventually bought by the government, which operated the attraction until 1988 when a legal dispute saw the cave's closure. After 18 years, Ruakuri was reopened, complete with underground lighting, a grand spiralling entrance that sits away from the sacred burial site entrance, and a nod (in the form of a cavern) to the land owners and original tourism operators.

As we walk, our guide indicates other points of interest amongst the echoey depths. Like the ceiling that looks like globules of caramel coloured melting wax. It reaches down towards us in smooth edged spikes - stalactites that have taken centuries to form.

Developed drip by painfully slow drip, a stalactite grows just one cubic centimetre every 100 years. Their age and delicate structure make their unusual beauty all the more awe-striking. We amble by in appreciative silence.

Then: "See the glow worms?" Our guide points to a smattering of shining dots on our right. "You've actually been lied to for the past 120 years," he says. We stop oohing at the insects and turn to him expectantly. "Glow worms are, actually, glow maggots.

"But as you can imagine, the 'glow maggot caves' didn't market so well, so hence the name glow worm!"

Whether it was the name that appealed or the sheer brilliance of the tiny, shiny insects, the glow worms have been a leading tourist attraction since the 1800s.

The glow worms found in Waitomo - Arachnocampa Luminosa - are unique to New Zealand. The shimmering maggots pop up in many dark, damp places in this area, but the most spectacular display is certainly within the cave system dubbed 'the Waitomo Glowworm Caves' - my next destination.

Unlike Ruakuri, where the walls curve in snugly and fierce stalactites bring the ceiling close, the Glowworm Caves are vastly spacious. I meander past cream coloured spikes and knobs, delicate columns that look like stretched toffee and a decorative limestone shaft where a waterfall once ran.

Approaching the underground river the air becomes cooler and the light softer. Soon we are in darkness and, as our eyes adjust, shimmering dots begin to appear, as if someone is pricking holes in the ceiling, letting the light in.

As dazzling as the glow worms' luminescence is today it must have really been a sight for explorers Tane Tinorau and Fred Mace who ventured into Waitomo's caves in 1887. On a flax raft with nothing but candles lighting their way the pair floated through what is now the Waitomo Glowworm Caves where they discovered the glittering underground spectacle. Several visits later the pair found an entry point from the land (as opposed to the river), which is the same entrance we used just moments ago.

We board our boats and begin gently floating upon the river. Everybody falls silent - awed by the thousands of glow worms twinkling from the cave ceiling. Looking up, the effect is like scanning a brilliant, clear night sky. It's so dark I can't see the people in front of me. All I hear is a melodic dripping and the ripple of our boat slicing slowly through the cool water as we make our way through the twisting limestone maze of Waitomo's famous caves.

Amelia is Content Editor of the New Zealand travel and tourism website www.fourcorners.co.nz.

Amelia visited Ruakuri Cave and the Glowworm Caves courtesy of the Legendary Blackwater Rafting Company, Tourism Holdings Ltd and www.fourcorners.co.nz