The lake spread below me was the brilliant blue of a painter’s palette so seldom seen in reality. The land around it was starved, blasted and desiccated, rocks and ridges jutting as if the bones of the earth were showing through. At the edges of the horizon, clouds floated over hills and farmland, as distant and unfocused as the edges of a dream. Here nothing grew. Nothing moved.

The Tongariro Crossing is not your average day walk, and the climb to the summit of Ngauruhoe is not your average side trip. For one thing, it’s 20km long and its high point is 700 vertical metres above the starting point. Taking the side trip adds another 3km and 487m of climbing on what is, essentially, an enormous, unstable mound of gravel. For another, you’re walking through a volcanic wasteland. Everything is bare and dry. At times the air becomes thick with the smell of rotten egg. Wisps of steam puff from beneath rocks at the side of the track. The hundreds of other walkers cannot detract from the weird, alien otherworldliness of the place – in fact, they only enhance how out of place humanity is here.

For me, climbing Ngauruhoe put the area I was walking through into perspective – and gave meaning to the word “challenge”. Each step was an effort, as the mountain’s loose surface slid away beneath my feet. I felt exposed on the sheer slopes, without any path or marker to guide me, without any trees to make the empty space around less imposing. But then there was the view behind and to the sides… a testament to the power of nature.

The earth’s power has long been close to the surface in and around the Tongariro National Park. The Taupo Volcano, which at present is a caldera filled by Lake Taupo, was responsible for the most violent eruption of the last 5000 years. This eruption devastated 20 000 km2 of land around the volcano and its effects were observed by the ancient Romans and Chinese. Lake Taupo is visible from the track, water distant, peaceful and gently ruffled, but closer by is evidence that the area hasn’t finished with eruptions quite yet. White clouds of steam billow from across the valley where the hillside is split open, revealing rock in powdery white, sulphurous yellow and rusty reddish brown. Every now and then the smell of sulphur drifts across in the wind.