I became fascinated with the kingdom of Mustang after I caught a glimpse of this beautiful desert valley on my first trek in 1980 when I was descending  from the Gangala Pass on the Annapurna circuit. At the time, Mustang, nestled between Nepal and Tibet, was its own separate kingdom. and was closed to tourism.   It wasn't until 2014 after it had  recently become part of Nepal,  that I finally fulfilled my wish.