Poised in delicate, often hazardous balance with the liquid natural world the fabric of the man-made city rises out of the water and is reflected in it. The earth of Venice, a tissue of alluvial silt, is upheld and given form by a vast subterranean endoskeleton of wooden pilings supporting buildings of splendor with their feet in the mud. The air of Venice carries both heat and swells from North Africa's deserts and envelops life like liquid gauze. And fire, the most volatile of the four elements, has both destroyed and redrawn swaths of the city and fed the industry and commerce of a trading nation.