The Bolsena lake, the fifth largest in Italy, is located in the upper Lazio region, on the border with Umbria and Tuscany, in the main caldera of the Vulsinio volcanic complex. It has an elliptical shape, an area of 114.5 square kilometers, a perimeter of 43 km, a maximum depth of 151 m, two islands, Bisentina and Martana, residues of volcanic craters, numerous tributaries of modest extent and a single outlet, the river Marta, which rises from the port of the homonymous town and flows into the Tyrrhenian Sea. It is mainly fed by rainwater, to a lesser extent by springs, small ditches included within the catchment basin, and by the seabed, where there are numerous gas springs, thermal waters (which reach temperatures of 40 ° C) and water rich in dissolved minerals. It is the largest lake of volcanic origin in Europe, it was formed in fact with the collapse of the volcanic Vulsinio, which after the lava eruptions has emptied and collapsed on itself, forming a huge caldera, slowly filled with water. The lake bottom is very irregular with many roughnesses while two beautiful islands, Bisentina (Kmq 0.17) and Martana (Kmq 0.10), both rich with Mediterranean vegetation, contrast the blue of its surface. the naturalistic features that distinguish it, there are two of particular interest: the "sesse" and the anomalous wave. The first are sudden variations in the level of inland waters, similar to the tides, but unlike these, completely unpredictable. Determined by atmospheric pressure or winds, they can even reach 50cm.
The second, more frequent and visible with calm lake, is a wave that presents itself with a front of vast proportions, which strengthens as it progresses until it breaches violently on the coasts. In the lake there are many fish and various species.The main present are: the excellent whitefish, pike, perch, the largemouth bass, the carp, the tench, the rudd (here improperly called lasca) and finally the small dairy, which is often prey to predatory fish and waterfowl. Given the abundance of food and protection reserved for them, the presence of waterfowl, especially migratory birds, is very high. Fishing boats are very special and almost unchanged from the remote era: in fact, the fishermen remain standing, using asymmetrical oars, with the front only propeller and the rear combined action, used in fact as a rudder. From July 23, 1884, the day when a steamboat was launched from the pier of Bolsena, they were replaced by small engines. On the shores of Lake Bolsena many small taverns were built, often in the old fishermen's huts, where enjoy dishes based on fish from the lake. The inhabited centers, rich in history, both on the banks and on the ridges of the Volsini mountains, are many. Starting from Bolsena and following the panoramic road clockwise, they will be in order:
Bolsena , the city that gave its name to the lake.
Montefiascone, with the most beautiful overall view of the lake.
Marta, the main and active port of the fishermen.
Capodimonte, on the picturesque promontory that extends towards the lake.
Valentano, with its wide panorama dominating the basin of the lake.
Gradoli, on a tufa spur inside the crater enclosure.
Grotte di Castro, retains the charm of the medieval structure.
San Lorenzo Nuovo, a perfect example of an eighteenth-century urban plan.
Bisentina Island, attractive and sinuous as a beautiful woman.
Martana Island, the famous island of the Queen Amalasunta.