Charred buildings, sunken ships and scattered shrapnel in the port of Mariupol remain a stark reminder of a siege endured by the Ukrainian city recently captured by Moscow during a military campaign in its pro-Western neighbour. After nearly two months, the fighting in the battered city and its strategic port has mostly stopped, but the sound of explosions still echoes from the Azovstal steel plant: the last stronghold of Ukrainian forces in the city.