Qah-Qaha fortress is a 4th century AD monument left from Kushan era. It is the second notable fortification built in Wakhan to secure Western Pamirs after Yamchun fort. Kaahka fortress is named after legendary hero and the king of Siahpushes- Qanqaha. Siahpushes are known to be fire worshippers and worn black qowns following this Zaroastian cult.
The walls were built of clay and stones and fortified by 56 towers with gun slots. Though the fortress is partly destroyed by time, water and winds the remnants still give a clear understanding of the size and its military might. Inner layout is the same as at Yamchun fort: citadel plus 3 grounds. The total length of rampart is 750 meters and its maximum width is 280m.
Its now known that were was a bridge over Pyanj near the fortress, which, according to travellers’ notes, existed in the area as late as the early of 20th century. Besides the bridge the fortress was securing this part of Wakhan Silk Road and blocked the access to fertile Shohdara and Gunt valleys for foreign invaders. Built over the rock outcropping it is clearly seen from the road and now host Tajikistan border guard unit.