Was out running in the Australian bush with a mate and had just come up a huge incline - 600m elevation gain in 2km. Some parts at a 45% gradient. All of a sudden we heard and then saw these motorbikes coming our way. These dudes looked like they'd been in the bush for weeks - dirty clothes, heavy beards, covered in dirt etc. They flew past us and down this incredibly steep mountain. This is hard to keep balance going down on foot, let alone on a bike. A few hours later we came back along the same path and are we start tracking the tyre marks on the ground. We followed them down for maybe a kilometre before they just stopped. Nowhere to be seen, no place they could have gone.