Just off-center in the heart of Vienna stood the tallest building Jack had ever seen – a cathedral with a dunce-cap tower topped by a curious symbol, a star wedged in the craw of a crescent moon, like a stick jammed into a shark's mouth. It seemed a prophetic map of the entire scene. Vienna was protected on the north by a canal that split away from the Danube, moated the city on that side, and later rejoined it. The bridges had been wrecked so no one could enter or leave that way. The entire remainder of the city was enveloped by the Turkish camp, narrowest at the two points where it touched the river, and, in the middle, as fat as Vienna itself – therefore, a crescent with the city trapped between its horns. It was a fluttering world of heathenishly colored tents and flags and streamers, with the ruins of Vienna's burnt suburbs poking out here and there like ribs of wrecked ships from a foaming sea.