Concordia is a junction of glaciers in the Karakoram of northern Pakistan where four of the fourteen highest mountains on Earth stand around a single field of ice and boulders, K2 among them, and it is reached by a week on foot up the Baltoro Glacier from the last village, the throne room of the mountain gods. The junction is a T: the Baltoro comes in from the west and the Godwin-Austen glacier drops in from the north, and the peaks stand at the corners, Broad Peak, the two Gasherbrums and, at the head of the northern arm, K2 itself, 8,611 metres of pyramid so steep it looks drawn. Concordia is a camp, not a place with anything built on it: tents go up on bare ice at about 4,650 metres, the temperature falls below minus ten as soon as the sun leaves the junction, and the sound all night is the glacier cracking under the tents.
The walk in is the trek. From Askole, the last village, the trail follows the Braldu river and then climbs onto the Baltoro, six or seven days of camps on the ice with the granite towers of the Trango group and Masherbrum passing on either side, each day starting before the porters strike camp and ending when the next tent platform has been levelled on the moraine. The porters are Balti men from the villages below, who carry a standard load of twenty-five kilograms for the whole week on the glacier, as the same families have done for more than a century since the first expeditions. From Concordia a further day up the Godwin-Austen reaches K2 Base Camp at the foot of the mountain, where the climbers' tents stand in summer and a memorial of tin plates carries the names of those who did not come down. The trek is two weeks there and back, with no villages, no roads and no rescue but a helicopter. Concordia is the one place where the giants of the Karakoram stand in a circle, and the only seat is a tent on the ice.