Annapurna is a ring of snow peaks in central Nepal with one gap in it, and a week of walking up that gap leaves you on the basin floor inside, ice and rock the whole way round. The highest of those walls is Annapurna I, 8,091 metres, the first mountain over eight thousand that anyone ever climbed, in 1950. It cost the two men who did it their fingers and toes, to frostbite and gangrene on the way down. The trek asks nothing like that. It follows the Modi Khola, a river milky with glacial melt, crossing and re-crossing it on suspension bridges strung high above the water, then tunnelling through rhododendron forest that reddens from mid-March. Most walkers break the climb at Ghandruk, a steep village of slate-roofed stone houses where dinner is dal bhat in a Gurung kitchen and the sons have long filled the Gurkha regiments.
Above the last houses the forest gives out, the valley pinches into a gorge, and the walls simply stop. Annapurna Base Camp is a glacial basin at 4,130 metres, ringed on every side, the peaks close enough to take the sky rather than the horizon. The Gurung call it the Sanctuary and mean it: by tradition no meat or eggs came in, and until recent decades no women or outsiders. At the entrance stands Machapuchare, the fluted fishtail peak, never climbed. A British team stopped about 45 metres short in 1957, and Nepal has issued no permit since. Arriving at midday buys you the view. Sleeping on the basin floor buys the place. Before dawn, with the air at its coldest, you step outside and for a few minutes the fishtail and the face of Annapurna I burn overhead while everything below is still blue. October and November hold that edge all day, once the monsoon has taken the haze with it. Most of the year it does not last: by late morning cloud comes up the gorge behind you and fills the basin to the rim, and the walls you walked a week to get inside are gone until dawn.