What's a GBAO permit?

What's mean GBAO and how to get a permit to visit the GBAO?

GBAO (Kuhistoni Badakhshon Autonomous Province of Tajikistan) is the frontier territory of Tajikistan and hasspecial permission entry (a stamp, which comes on a separate page of passport), which allows applicants to visit Khorugh, Darvoz, Vanj, Rushon, Ishkoshim and Murghob districts. Foreign citizens traveling to GBAO region should indicate in their application, under the section of 21 “purpose of visit” their intention to do so. It is required to submit a letter stating that the applicant is requesting a permit to enter the mentioned area.