Bulldozer levelling a sea salt mound at the Messolonghi salt ponds in a process called salt harvesting. The Messolonghi - Aetoliko lagoon system dates from the 14th century and is one of the most important of all Mediterranean salt lagoons with a very high salinity of 38 ppt (parts per trillion), or more in some areas. Almost closed off from the Atlantic Ocean, there is three times more evaporation here than there is rainfall or freshwater flowing into it from rivers. The unique landscape of the Messolonghi Lagoon, the largest lagoon in the country is said to produce 60 percent of the country's salt with a production capacity of about 120.000 tones of salt per year.