Italy is set to declare a state of emergency in Venice after the Italian city has been engulfed by 1.87m (6ft) high water levels, flooding its historic basilica and cutting power to homes. More than 80% of the city, a Unesco world heritage site, was under water when tides were at their highest.St Mark’s Square – one of the lowest parts of the city – is one of the worst hit areas.The city of Venice is made up of more than 100 islands inside a lagoon off the north-east coast of Italy. It suffers flooding on a yearly basis. Only once since official records began in 1923, however, has the tide been higher than it reached this week – hitting 1.94m in 1966.