I was in New Zealand and did this tour with Iain and Ryan on December 30, 2013. The ages of people in our group was 14-62.
It was the most amazing experience. Iain and Ryan make you feel very comfortable by double checking absolutely everything!
The 100m descent is beyond words. It's an awe inspiring view as you lower yourself into the canyon. At the bottom you can still enjoy this view for a little while before heading into the caves.
The caves are great to climb into and if you're claustrophobic, you don't need to worry about any small spaces in this cave. You can climb through a tight space when going to see the glow worms but you can also go around and still get to see the glow worms.
Iain and Ryan were fun and information with of course taking safety as the most important priority! They also take great pictures so I'd advise buying the USB after!
Just a tidbit of advice, when I do this trip again (and someday I will!), I'd bring a pair of biking gloves. There is a climb on a ladder (though safe because you're properly hooked up), gets a bit slippery and it would be an easier climb with gloves (it gets slippery).
You can't go to New Zealand without doing this tour! It was the highlight of the trip for all 7 in our group!
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