Passu Cones are called Tupopdan in Wakhi — "hot rock" — and the name doubles as an explanation. Sun strikes these south-facing walls so directly that snow slides off them all winter; the spires stand bare and grey-gold while the rounded giants around them keep their white domes. The highest cone reaches 6,106 metres, and no one climbed it until July 1987, when Andy Cave and John Stevenson found a line up its northeast ridge. Its north face is brutally steep: it gains about 1,700 metres of height while covering only a kilometre and a half of ground. The limestone is cut by ice and wind into knife-edge points that travellers took to calling the Passu Cathedral. Behind the ridge lies the ice that built this valley: the Batura Glacier, 56 kilometres long and the seventh-longest outside the polar regions, grinding down to a rubble-covered snout just north of the village.
Most people first see the ridge through a car window. The Karakoram Highway — on its way to Khunjerab Pass at 4,693 metres, the highest paved border crossing on Earth — swings out of a bend and the whole ridge fills the windscreen. Coming into Passu the white tongue of the Passu Glacier drops almost to the tarmac, clean ice where most glaciers here are grey with rubble. The village beneath is Wakhi: stone-walled fields, lines of poplar, families who crossed the mountains from the Wakhan between 1870 and 1948. In October their poplars and apricot orchards turn yellow and rust under the bare stone, the picture most people come for. Below the fields, a plank bridge on steel cables sways over the river at Hussaini. Drivers reach all of it through five tunnels now, built after a landslide dammed the Hunza in 2010 and drowned 19 kilometres of the old highway; the border above has run year-round only since December 2024.