Mare Mostrum is a reflection on the future of the Italian coastline and, most in general, on the relationship between human being and environment. In the last century, beaches and sea have become a symbol of the Italian identity that represents, with more than 7.000 kilometers of coastline, the heart of the Mediterranean: destination for millions of tourists every year. In 70 years this delicate ecosystem has been slowly replaced by a growing overbuilt: meter by meter, beaches, dunes, cliffs have been lost and replaced, usually, by industrial areas, second homes, illegal structures and beach facilities. Since mid-80s, 220 kilometers of coast have disappeared, at the rate of about 8 kilometers per year and now, according to ISPRA, the land cover is 45% of the seacoast.