Venice, Italy, is suffering from a combination of subsidence—the city's foundations slowly sinking into the mud on which they are built—and rising sea levels. In the worst-case scenario, it could disappear underwater by the year 2100.
Alessandro Gasparotto, an environmental engineer, is one of the many people trying to keep that from happening. Standing on a large mudflat in the center of the Venetian lagoon, he pushes a hollow three-foot-high metal cylinder called a piezometer into the thick black mud. This instrument will measure how groundwater moves through the sediment as the lagoon's tides rise and fall. Knowing what's happening under the mud is crucial for understanding whether, and how, vegetation can grow and eventually transform this barren landscape of mud into a salt marsh.