Recognising the special nature of this old, tiny kingdom, the Nepalese have imposed a surcharge for anyone wishing to trek past Kagbeni, the border of Upper Mustang. With legal trekking groups only being allowed in for the first time in March 1992, you would be part of a small privileged minority to visit this remote outpost of Nepal. Mustang is the old kingdom of Lo. Actually the capital of the Mustang district is Jomsom, but the real Tibetan-style district lies north of Kagbeni and is usually referred to as Upper Mustang. The real capital, Lo Manthang, where the present king lives, is a fantastic square-walled town sitting on the 'Plain of Prayers'. Mustang has an average elevation of 13,200ft/4,023m and is located to the north of the mountain giants of Dhaulagiri and Annapurna and is therefore north of the main Himalayan range and geographically is part of the highlands of Tibet. It is a vast high arid valley, characterised by eroded canyons, colourful stratified rock formations and has a barren, desertlike appearance.