Upper Mustang is a forbidden area in the upper regions of the Himalayas in Nepal. As the place lies near the Tibetian border, the culture and traditions over there are almost identical to villages in Tibet.
Upper Mustang used to be a separate kingdom inside Nepal in the past times. There's still an ancient royal palace in the capital Lo Manthang. As it was a restricted area, very few used to visit the area. So, it has less contact with the outside world and is untouched by modernization. Lately, the area was opened for international travelers for trekking, and a lot of visitors visit the area to discover ancient mysteries. Not only mysteries, trekking to Upper Mustangallows you to meet real mountain people, understand their culture.
The best time to visit the area is March to May and November to September. Since the area receives less rainfall and is dry, it is a suitable place to visit during the monsoon too.