Trekking in Nepal differs with scenic perspective like green hills till 4000 meters, brown hills or lets say dessert till 5000 meters to White snow above 5000 meters. Upper mustang trek in Nepal does offer dessert scenery and Tibetan cultural heritage. Many people call it as a lost kingdom, forbidden kingdom, hidden kingdom and so on. This is definitely the unique place to visit which brings back to memory of medieval time. I felt like i was living in medieval time, i forgot that i was born in 21st century haha. I trekked to Lo-Manthang, the capital city of Lo (upper mustang) while there was Tiji festival. I found that Tiji festival has been practiced by the locals for 500 years (since 17th century). Most of the Monasteries have puja everyday where you can go and meditate while monks are reciting mantras.