Undara, North Queensland: Where to see lava tunnels in Australia

Standing in darkness I feel and hear, rather than see, hundreds of microbats flapping past my face. With unerring accuracy, they fly centimetres from me without touching. Bram, our guide speaks quietly: "of course, with this much flying food there are predators ... when I turn on my torch you'll see snakes hanging from the trees just above us." He does. There is.

We've come to spend 24 hours exploring the world's longest lava flow from a single volcanic vent in modern geological time, but it turns out that there's more to Undara than that. The afternoon game drive that leads us to the bat encounter also introduces us to pretty-faced wallabies that certainly live up to their hype among the dour, shaggy common wallaroos. At the summit of Sunset Bluff we see to the distant horizon and the region's geology came into sharp relief. It's scrubby, dry savannah woodland and though we're almost directly west of Mission Beach and about 260 kilometres from Cairns, it feels a long way from the Reef. Indeed, the geological activity that has brought me here seems quite un-Australian. Volcanoes in Queensland?

The Undara volcano erupted 190,000 years ago as part of a cluster of volcanoes that included the Boomerang and Mount Razorback volcanoes. Molten rock poured out of it at a rate of up to 1000 cubic metres per second flowing along the course of existing river beds, filling one creek for a distance of 90 kilometres and another for more than160 kilometres .

In Australia rock is something you walk on, drive on, or throw. Red rivers of lava are the stuff of television news and the mechanics of lava cooling a mystery. In fact, the outer surfaces of the flow cool first like the skin on custard. The lava in the creek bed becomes a tube with a molten core, rather like a Mars Bar with a 10-metre diameter. When the volcano stops the core continues to flow, leaving a long hollow tube.

The remarkable beauty of a faceted lava tube is a symphony in stone. We're on a morning guided tour inside a lava tube. The roof of the tube collapsed eons ago and we descend stairs to the floor through vegetation thriving in the volcanic soil. Another section of roof has collapsed leaving the Archway, perhaps Undara's best known feature. During the tube tour we venture into Stephenson Cave and Ewamian Cave, named after the original people of this land.

Our guide is Bram Collins, owner of the attraction known as the Undara Experience which also provides accommodation and in which we stay. Four generations of the Collins family ran Rosella Plains Station where Undara is situated. In 1987 Bram's father Gerry proposed Undara be proclaimed a National Park with access by tours from a lodge operated by the family as the tubes and their occupants could be harmed by unsupervised visitor access. Bram is also closely involved with the conservation-orientated Savannah Guides network across northern Australia.

At the Undara Experience you can stay in repurposed and restored Queensland Railway carriages that Gerry found decommissioned on a siding in Mareeba. Each unit has a lounge room and a double bedroom with ensuite and the original QR wire luggage racks. Dinner is served in the Lava Lodge's vast amphitheatre and breakfast is a bush barbecue.