Afghanistan, Balkh. Man on donkey, walls of old city Balkh in the background, northern Afghanistan. The mud walls of the Bala Hissar (fort) at Balkh are mostly Timurid period (1370-1506) in date but are built on early, part Kushan-era foundations. The Timurids extended the walls to a circumference of about 10km and, in places they still stand at 20 metres high