The gorge is the work of a single creek, often called Galah Creek or Porcupine Creek, doing one thing for an unimaginably long time. In the dry season it is a gentle string of waterholes scattered along the gorge floor, easy to wade and cool to swim. In the wet, it transforms. Storm runoff funnels off the surrounding plateau and channels into the chasm, and the creek becomes a raging cascade with the cutting power to deepen the canyon it has already excavated up to forty metres below the immediate plateau. To descend the walking track from the rim, dropping roughly 120 metres toward the water, is to climb down through the very process of erosion, watching the layers change as you go. The Pyramid, an isolated monolith of multicoloured sandstone, rises from the gorge floor where the canyon widens, a freestanding landmark left behind as the water cut around it.

Those colourful walls are a library of deep time, and the gorge slices clean through hundreds of millions of years of Queensland's past. The oldest layers at the base, the Betts Creek Beds, formed in a coastal swamp during the Permian period, when forests of the seed-fern Glossopteris grew, died, and rotted into the dark muck that would slowly compress into coal. You can still find their fossil leaves pressed into the mudstone. Rising sea levels then buried that swamp under river sand, laid down through the Triassic and Jurassic as the Warang and Blantyre sandstones, channel after channel of grit recording ancient rivers that ran here when dinosaurs walked the continent. Where mineral-rich groundwater once seeped through cracks, it leached iron from the stone, which is why the same sandstone shifts from deep red to yellow to ghostly white as your eye travels up the cliff. The whole sequence is finally capped, in places, by a layer of rock baked hard by ancient volcanic basalt that flowed across the top.

Long before it had a name on any map, this gorge was a place of life and meaning for the Yirandali people, the Traditional Owners of the country around Hughenden, whose language is also recorded as Yirandhali or Pooroga. In a hard, dry land, a permanent source of water and shade like Porcupine Gorge was precious beyond measure, a reliable refuge when the surrounding plains baked. Their presence is written into the rock itself: at a spot in the gorge known locally as 'the Tattoos,' Aboriginal rock drawings remain on the stone. The Yirandali welcome visitors to their traditional country and ask, simply, that the place be treated with the respect it has always been owed. To walk the gorge today is to move through a landscape that has been valued, watched over, and lived in for a very long time.

Today the gorge is protected within Porcupine Gorge National Park, which sprawls across more than 5,400 hectares and runs for over 25 kilometres along the creek. For travellers crossing the long, hot inland, it arrives like a secret. The lookout sits about 60 kilometres north of Hughenden, with a camping area and the steep walking track a little further on, dropping hikers down into the green heart of the canyon. After the open glare of the savannah, the gorge floor is another world entirely: shaded, echoing, alive with birdsong, the cliffs honeycombed with overhangs and the waterholes mirroring the painted walls. Sandstone weathers slowly into strange shapes here, and flash floods keep carving. The canyon is not finished. It is simply caught, for now, in the middle of being made.