Late last month, swimming was banned along 15 km of beaches in Liguria (Italy) after toxic algae on relocation from tropical seas sent over 100 adults and children to hospital, suffering from breathing difficulties, high fever, stomach cramps, etc.

Further west, along the Catalan coastline, around 11,000 people have been treated for stings this summer after an invasion of jellyfish in Spanish waters.

(Detail from the Medusa of Caravaggio)