Venice is made up of 124 islands, 183 canals and 438 bridges, with water constantly flowing in and around it. As the video below explains, the city has historically developed an elaborate way of defending itself against the seas. But occasionally mother nature wins out, and floods take their toll on the city. This year it's particularly bad. Heavy rains and strong winds have left Venice 70% submerged, with water levels reaching 60 inches. It marks the sixth worst flood recorded in the past 150 years. You can find footage above, and a pretty remarkable photo gallery over at The Atlantic. And then another compelling set at Boston.com.