Crossing the Mongolian steppe in a mud-spattered van

Ablond border guard wearing long braids waves us out of Russia - and the road immediately turns to dirt. Our van shudders through a barren no-man's-land deep in the rocky Altai Mountains, but on our arrival, we find that the gate to Mongolia is locked.

The country is closed for lunch.

Thirty-nine days and 14,500 kilometres after having left London as a participant in the Mongolia Charity Rally, our once shiny, finely-tuned van is covered in mud and sounding like the automotive equivalent of a 90-year-old smoker. There are still another 1,800 kilometres to go to our destination, the Mongolian capital, Ulan Bator, across some of the harshest and least-populated land in the world. I'm worried our van isn't going to make it - but first, someone needs to unlock the gate.

The remote Tashanta-Tsagaannuur border lies in the region where Russia, Kazakhstan, China and Mongolia converge. The highway on the Russian side of the border rises steadily to this point, the pine trees and wooden farmhouses of Siberia giving way to the golden grassland of the mountain steppe. It's Mongolia's only western border with Russia, and cars are lining up behind us.

At 2pm, the gates open. Importing a car into Mongolia takes a lot of paperwork. I've heard it can take five days, so we stocked up on vodka in the only store in Tashanta. But just after 6pm, a border guard beckons us over and accepts US$10. We're in.

The far western Bayan-Olgii province is majestic, high and cold, the vast steppe stretching to glacier-topped mountains that rise like jagged shark teeth. Skittish goats and shaggy baby yaks wobble past. Men and women in traditional deel, worn like thick bathrobes, bounce by on motorbikes. Massive golden eagles, their wingspan up to 2½ metres, perch like sentinels, some on rocks, some on the road and others - those owned by people - chained to posts or tyres. As Genghis Khan did before them, the eagle hunters of Mongolia train their birds to hunt wolves.