Nepal; yak transport in the Khumbu, 1986. Sherpas drive a pair of heavily laden yaks along a narrow path on the long climb from Lukla (altitude 2827 metres) to Namche Bazar (3446 metres), the main town in the Khumbu region. The yak is the beast of burden in the Khumbu as well as providing wool, milk, cheese and butter. Yak butter is burned in votive lamps and drunk in tea. The animals command a high price and are carefully nurtured by their owners.