The Ghazni Citadel (Bala Hissar) rises on a rocky outcrop above the old city, a sprawling mud-brick fortress walled and re-walled across more than a thousand years. The earliest surviving structures date from the Ghurid period in the 12th century — after the Ghaznavid capital had moved south — but parts of the foundations go back further. The British army used it briefly during the First Anglo-Afghan War; the citadel was the centre of fighting in 1839.
What remains today is rugged and atmospheric: weathered curtain walls, towers at unequal intervals, a few interior chambers. There are no official tours and visiting depends entirely on the current security situation. The view from the upper terrace across the old town's flat rooftops and out to the bare mountains is the best in Ghazni.