Mustang was an ancient forbidden kingdom, bordered by the Tibetan Plateau and sheltered by some of world's tallest peaks, including 8000-meter tall Annapurna and Dhaulagiri. Strict regulations of tourists here have aided in maintaining Tibetan traditions. Upper Mustang was a restricted demilitarized area until 1992, which makes it one of the most preserved regions in the world due to its relative isolation from the outside world, with a majority of the population still speaking traditional Tibetic languages. The name Mustang is derived from the Tibetan word meaning, Plain of Aspiration. Upper Mustang was only opened to foreigners in 1992 (annual quota at present of 1,000 people). It is a popular area for trekking and can be visited year round (regardless of season).