Marble blocks litter the track to Harwoods Hole like the carcasses of long dead, strange and forgotten animals.

Sharp ribs still protrude and holes have worn through the slippery rocks, where once a stream had eaten its way through the marble mountain, known as Takaka Hill.

In places, the rocks tumble densely around the track which follows a dry stream bed, whose waters have long since disappeared to caves and channels tunnelled through the hill, deep below.

Clamber carefully over the marble, polished to a slippery shine in places, until eventually reaching a jumble of boulders and stunted trees which mark the edge of Harwoods Hole. The hole plunges 176m straight down to an underground river and there are no barriers around the edge.

Head up to the nearby Gorge Creek lookout, where the efforts of the walk were amply rewarded. The track tops out onto a maze of fluted rocks which leads to views over Takaka Valley.