Five minutes walk north from the campground is the Punakaiki Cavern, hidden away on the eastern side of the main road. Car parking is available on the sea-side of the road, slightly north of the cavern. Take care when crossing the road.
The cavern features glow worms, the larvae of a large mosquito-like fly. In order to survive they build traps consisting of vertical hanging threads of silk. The silk thread is studded with sticky droplets of mucous to catch small insects that are attracted by the light. In actual fact they are not worms at all.
There are also stalactites in the cavern, formed when calcium carbonate and other minerals, drip from the cavern ceiling over time, eventually creating hanging formations tapering down to pointed tips, resembling solid cones.