Qaila Jangi became infamous during the American backed defeat of the Taliban by the Northern Alliance, when video footage of US and UK soldiers appeared on television sets across the world, firing into the rebelling Taliban prisoners and an American Taliban was taken prisoner - one of the few survivors.
The uprising started right after the death of an American CIA Agent. There is a plaque commemorating his death but nothing about the hundreds of more Afghans that were killed in the hours afterwards.
After the fall of Mazar-e Sharif to Warlord General Dostum and western advisors, truckloads of Taliban prisoners were herded into the fortress, a large facility half an hour outside of town.
The fortress is divided into two sections, both large empty spaces and the Taliban were placed in one that had some vegetation and a few brick and concrete buildings. The walls are sloping inwards from the outside and vertical from the inside, probably a strong reason why the Taliban were not able to scale the walls and escape after capturing weapons, and why the Afghan and western soldiers were able to trap them in their area by sealing the one exit/entry point and controlling the walls.