Inland Pack Paparoa National Park. There are parts where it would be quite unwise to wander off the path. Sometimes its possible to hear, but not see, waterfalls that are obviously large and then the realisation comes that they are subterranean and that you are walking over the roof of a vast cavern.
Creeks often vanish underground only to resurge farther on.
The origins of this track were as a means of getting around a particularly difficult piece of coast line by the early settlers and gold miners. Essentially the track follows on up the Punakaiki River from the West Coast, over a low saddle, across the Porarari River, through the bush and eventually down Fossil Creek. It then continues down Dilemma Creek to its confluence with the Fox River, and down the Fox to the coast again. Definitely not the place to be after recent or impending rain, as the rivers rise very fast. There are something like seventeen fords and there is no escape from the river in flood.