UNESCO has asked the Italian government to restrict access by huge cruise ships to Venice after the grounding of the Costa Concordia.
In a letter sent to the Italian Environment’s Minister on behalf of UNESCO's director general Irina Bokova, the agency urged quick action "to develop alternative plans for maritime traffic" in Venice.
Experts believe that big ships cause water tides that erode building foundations, pollute waterways and dwarf monuments in the city.
Up to 300 liners enter the Venetian Lagoon every year, which is a UNESCO World Heritage Site.
According to calculations by researchers, Venice may become unsuitable for living by 2028.