Saving Venice from the marauding sea.

• Position: Brief Article

Venice, Italy's historic city of canals and gondoliers, is planning to defend itself in the 21st century by building massive, swinging gates. The idea may conjure images of medieval drawbridges, but these high-tech gates won't protect citizens from foreign invaders. Instead, they have been designed to keep the marauding sea at bay.

After a centuries-long war with flooded streets, the Italian government is expected to decide soon whether to proceed with a public-works project that would build a series of floodgates at three inlets along the lagoon surrounding the city. The gates, which will rest on the sea floor and swing upwards in response to rising tides, will cost $34,000,000,000 and take several years.

Three Massachusetts Institute of Technology, Cambridge, professors have...