The final climb before Almaty was most remarkable for quite how easily we dismissed it. This was more than a vertical km climbed again up to an altitude above 3000m, but after a day's rest at the nomad games it passed like a breeze, my History of the Silk Roads audiobook and the East India Company's interference in Afghanistan was ample auditory fuel, not a beat in sight. It was not the climb that shortened our breath and strained us to our limits but what lay at its top.

As we approached the end of the mapped elevation, the road was swallowed into darkness on the mountainside, a one and a half lane tunnel built in the 1980's lay before us. No issue we have done many and we've got a formula, put on the lights, stay together, earphones in to block out the truly hellish noise, and get through it over and done with as fast as possible. A man in a tunnel office was waving his arms about something, but we put our heads down and plunged into its concrete throat.

The first noticeable difference in this tunnel was the road quality, potholes were poorly illuminate and the narrow road forced us right over them. The poor road surface also meant stone dust swirled and brought visibility within 10m, I pulled up my neck buff and squinted - feeling my the edge of my eyes caking in grit. We plunged further in, knowing we were only several hundred meters into 3km of this ordeal.

I then began to feel pins and needles ripple across my scalp, my depth of breath shortened into juddering gasps, it wasn't the altitude I had been fine outside at the same height. I was unsure if I was developing a tightening tunnel of vision, or if that was merely the affect of my surroundings. I the realised the final and most significant difference between this and other tunnels we had done, I don't remember seeing a ventilation fan above, others had had one every 30m or less. These bodily effects were exponentially coming on, my cranium was now feeling numbed and very sensitive simultaneously, as the cars and trucks roared by. I thought 'this is how people commit suicide, enclosed spaces and exhaust gas, carbon monoxide poisoning.'

We weren't yet halfway but I made the call and signaled an instant retreat to Rob, his muffled head nodded, and we cycled even faster back the way we came. With every pedal-stroke towards fresh air I felt better - certainly more psychological than physiological but vital nonetheless.

We burst into the light, looked at each other anxiously, as the tunnel official waved his arms again, this time in an exasperated 'told-you-so'. I wouldn't paint this as a near death experience, but it would have been a very shoddy situation if one of us had passed out in the tunnel with the other trying to help in a dizzied and desperate state, cars flying by.

In the end a couple of scrap haulers put our bikes in the back as we all squeezed into the cabin, and we were at the other end of the tunnel before we could even bring ourselves back into good focus. The dramatic descent did this for us afterwards, a real sense of flow can occur when surrounded by stunning scenery and peddling very little for a few hours.

This brought us to the outskirts of Bishkek, where we met our very first walker, Ben from Czechia. Walkers are truly a wondrous breed, people think world cyclists have a screw or two loose, tour cyclists think the same of intercontinental walkers. Ben was on a pilgrimage to India and had been on the road for 3 years, which works out as we estimated he was slower than us by a factor of 4. He was a peace and love guy walking with a white flag in open toed sandals, and in his words he was after an 'enlightenment experience on the road some time'. We weren't persuaded it works like that, but credit where merit is due.  

The next few days were a very conscious effort to Almaty: through Bishkek, across the border, along Kazakh plains that shared the same type of emptiness of Mid-West America. The journey is harder to savour when the destination is 10 days away from cycling, surrounded by loved ones, and access to non Central Asian cuisine.