You step onto the walkway and the canyon drops away immediately below you.
The Jadh Ganga is maybe 300 metres below, green and fast. The cliff face you are attached to is vertical granite. The walkway is 1.8 metres wide, which is comfortable in theory and narrow in practice when you look down. You put your hand on the wooden railing, which is solid, and you walk.
The mountains above the canyon are enormous. The Nelong Valley is visible ahead — wide, dry, completely unlike the green Bhagirathi valley you drove through this morning. The Tibetan Plateau is in the same direction. Somewhere beyond that, Heinrich Harrer was walking in 1944.
It takes 20 minutes. When you reach the far end you sit on a boulder and look back at the cliff face and the walkway and it looks more improbable from this side than it did from the other.
You walk back. The return direction shows you things the approach hid. The canyon below looks different going east. You hear your own footsteps on the wood.