Pao An was once a frontier stronghold... Remains of its fortifications, flame-struck in that afternoon sun, could be seen flanking the narrow pass through which once emptied into this valley the conquering legions of the Mongols. There was an inner city, still, where the garrisons were once quartered; and a high defensive masonry, lately improved by the Reds, embraced about a square mile in which the present town was located.