Tanggula Pass is a place of thin air and big silence. At 5,231 metres on the Qinghai-Tibet Highway, it is one of the high points of the road that crosses the plateau from Golmud to Lhasa, and it marks the boundary between Qinghai and the Tibet Autonomous Region. There is little here but a stone marker, a wide view and a landscape of bare brown hills dusted with snow. You will feel the altitude as soon as you step off the bike: a pounding head, short breath and a strange slowness in your limbs.
The pass lies on the watershed between the rivers of the Yangtze to the north and the Salween to the south, and the glacier-fed streams nearby are the headwaters of the great Yangtze, which runs thousands of kilometres to the East China Sea. The plateau around it is a high, cold desert, home to wild yaks, Tibetan antelope and wild asses, and the horizon seems endless.
The railway runs alongside the road here, and the Tanggula station on the Qinghai-Tibet line, at over 5,000 metres, is among the highest in the world. Engineers had to deal with permafrost, using cooling pipes and raised tracks to keep the ground frozen, and the highway has a similar story of repair and renewal. The road itself is paved and generally in good condition, but trucks carrying freight up and down the plateau are heavy and slow.
Travel here needs planning. The altitude can cause serious sickness, and riders should acclimatise for days on the plateau before pushing over the pass. Foreign visitors need permits and typically a guide, and independent travel is restricted. Weather is severe, with snow possible in any month, strong winds, and temperatures that can drop far below freezing even in summer. Fuel is available in the towns on either side, such as Amdo and Nagqu, but not on the pass, and you should fill the tank in good time. Bring warm clothes, water and patience, and treat the stop as a short one.