100 meters underground. That's where I was headed. We put on full wetsuits, boots, harnesses, and helmets and went to the entry point of the caves for a quick lesson in rappelling.

We rappelled down the 100 meters, through this little hole, into the darkness of the cave below. I sang the whole way to keep myself from freaking out.

After the entire group descended and unclipped, we walked a short distance, hooked to a lead line, to the start of a zip line. One by one we were sent down the zip line. Did I mention they turned out all the lights as you were sent down the line? At the end of the line, we took off our harnesses and were given big black inner tubes which we were supposed to jump on on the underground river. The jump was a bit unnerving and my inner tube went one way and myself the other.

As we paddled along the underground river, we turned off our lights and were surrounded by the natural light given off by the millions of glow worms all over the tunnel. The sight was amazing!

As we floated back to where we hopped into the river, we left our tubes there and went walking through the caves, swimming at times, sliding down natural slides, squeezing ourselves through tight spots and underwater ledges such as the "birth canal". Walking under waterfalls that cascaded from the ground above, this truly was a different world.

The Waitomo Walkway winds through karst landscape--over rolling green hills scattered with limestone outcroppings and through a forest--leading to Ruakuri Natural Bridge, the scenic highlight of the hike, where waterfalls cascading over mossy rocks and limestone caves beg to be explored.

The trail starts across the Information Center and takes a minimum of three hours round trip. Just allow plenty of time, and bring torches. It gets very dark at night, scary for hiking back, but perfect for seeing hundreds of blue-green glowworms twinkling for free.

My husband, David, and I started out at 5:30pm on a sunny summer day in February. We followed the narrow dirt path up open grassy hills, crossing stiles when walking through pastures. At times it was difficult to tell if we were on the trail or one created by sheep. But orange poles periodically mark the way.

Once we lost the trail. Our apparent horse trail dead-ended at the road. Back on track, we climbed and descended another hill, crossed the road, and rambled into the forest. A sign read: "25 minutes to Ruakuri Natural Bridge." David had had enough. He was hot, thirsty, and tired of hiking. So he turned back, while I continued on.

The sunlight was quickly fading in the shaded canopy of trees, making me suddenly cognizant of time and the realization that I didn't have a torch to find my way back in the dark. So I decided to jog. The trail opened into pastures. Puzzled sheep stared at me as I whizzed by.

I crossed a swing bridge, and came face to face with a cow. The hilly trail seemed to go on and on. Tired from jogging, I slowed down to enter a magical canopy. Colorful finches fluttered beside me as I wandered through dramatic shoulder-high flax plants and fern trees.

I reached the Anuruni Cave carpark at 7pm. Empty. As desolate as the trail. (So much for hitching a ride.) A sign read: "Ruakuri Natural Bridge 45-minute loop ahead." And dusk was definitely darkening.

I hurried through the loop in twenty minutes, passing numerous limestone formations, a beautiful river, waterfalls, caves, hanging mosses and ferns, a swing bridge, and mysterious tunnels. But where was the Natural Bridge? I popped my head into a dark cave--SURPRISE! Two college-aged girls taking photographs of each other screamed when I entered, scaring me in return.

I spent the next hour with Sylvia and Charlotte exploring caves, finding the elusive Natural Bridge and taking their photo. They wanted to pose for photos every five steps . . . against ferns, inside every cave . . . but they were fun, and I enjoyed their companionship.

When we left, people were arriving with torches heading in to see the glowworms. I realized what they were up to but didn't tell the girls. It was late, and David would be downright mad.