Lake Bolsena is a crater lake

Crater lake

A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not...

 of central Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

, of volcanic

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 origin, which was formed starting 370,000 years ago following the collapse of a caldera of the Vulsini

Vulsini

Vulsini, also known as Volsini volcano, Vulsini Volcanic District, Vulsini Volcanic Complex and the Vulsinian District, is a circular region of intrusive igneous rock in Lazio, Italy, about to the north northwest of Rome, containing a cluster of calderas known to have been active in recent...

 volcanic complex into a deep aquifer

Aquifer

An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...

. Roman historic records indicate activity of the Vulsini volcano occurred as recently as 104 BC, since when it has been dormant. The two islands in the southern part of the lake were formed by underwater eruptions following the initial collapse of the caldera.

The lake is supplied entirely from the aquifer, rainfall and runoff, with one outlet at the southern end. A sewage treatment plant filters most of the raw sewage from the surrounding communities. Constructed in 1996, it features pipelines transporting the sewage from every major community around the lake to the treatment plant on the Marta River; that is, no effluents enter the lake. Fertilizers are a second source of contamination. However, the chemical content of the lake is monitored at several stations around it.

Lying within the northern part of the province of Viterbo

Province of Viterbo

The Province of Viterbo is a province in the Lazio region of Italy. Its capital is the city of Viterbo. It is bordered to the north by the Province of Grosseto and Siena, by the north-east with the Province of Terni and Rieti, in the west by the Tyrrhenian Sea and south by the Province of Rome.It...

 that is called Alto Lazio ("Upper Latium") or Tuscia

Tuscia

Tuscia is a historical region of Italy that comprised the southern territories under Etruscan influence. While it later came to coincide with today’s province of Viterbo, it was originally much larger, including the whole Region of Tuscany, a great part of Umbria and the northern parts of...

, the lake has a long historic tradition. The Romans called it Lacus Volsinii, adapting the Etruscan

Etruscan civilization

Etruscan civilization is the modern English name given to a civilization of ancient Italy in the area corresponding roughly to Tuscany. The ancient Romans called its creators the Tusci or Etrusci...

 name, Velzna, of the last Etruscan city to hold out against Rome, which was translocated after 264 BC, and its original location today has not been securely identified. The lake is bordered on one side by updated forms of the Roman consular road Via Cassia

Via Cassia

The Via Cassia was an important Roman road striking out of the Via Flaminia near the Milvian Bridge in the immediate vicinity of Rome and, passing not far from Veii traversed Etruria...

. In addition to the historic sites of all periods, Lake Bolsena is currently surrounded by numerous tourist establishments, largely for camping, agrotourism and bed and breakfasts.

One third of the lake was donated to the Church by the noble family Alberici of Orvieto. In recognition of the donation the Alberici family was honored with a ceremony three times a year performed by the Bishop of Orvieto.

Geography

The lake has an oval shape typical of crater

Volcanic crater

A volcanic crater is a circular depression in the ground caused by volcanic activity. It is typically a basin, circular in form within which occurs a vent from which magma erupts as gases, lava, and ejecta. A crater can be of large dimensions, and sometimes of great depth...

 lakes. The long axis of the ellipse

Ellipse

In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...

 is aligned in a north-south direction. The bottom is roughly conical reaching a maximum depth at a point in the middle. The entire lake is surrounded by hills on the flanks and summits of which are the comuni. The watershed was home to 22000 permanent residents in 2004, 35000 in the summer season.

Elevations on the north of the lake are the highest, with a maximum of 702 m (2,303.1 ft). As the lake is at 305 m (1,000.7 ft), no hill is more than 397 m (1,302.5 ft) higher than it. On the northern rim of the caldera is San Lorenzo Nuovo

San Lorenzo Nuovo

San Lorenzo Nuovo is a small town and comune in the province of Viterbo, in the Latium region of Italy. It is an important agricultural center for potatoes, olive oil, garlic, onions, cereals and grapes. A second source of revenue is tourism.-Geography:...

 ("New Saint Lawrence"), which was moved from an older site (a hypothetical San Lorenzo Vecchio, "Old Saint Lawrence") further down the slope to avoid malaria

Malaria

Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

. The northern shore of the lake once featured marshes, breeding grounds for the mosquitos that carry the disease. Currently it is agricultural. At the site of old San Lorenzo are Etruscan

Etruscan civilization

Etruscan civilization is the modern English name given to a civilization of ancient Italy in the area corresponding roughly to Tuscany. The ancient Romans called its creators the Tusci or Etrusci...

 antiquities. To the north of San Lorenzo Nuovo and the caldera rim is Acquapendente

Acquapendente

Acquapendente is a city and comune in the province of Viterbo, in Lazio . Acquapendente is an important centre for the agricultural production of vegetables and wine, and has a tradition of pottery craftmanship.-History:...

.

The hills to the east are 600 m (1,968.5 ft) to 650 m (2,132.5 ft). Bolsena

Bolsena

Bolsena is a town and comune of Italy, in the province of Viterbo in northern Lazio on the eastern shore of Lake Bolsena. It is 10 km north-north west of Montefiascone and 36 km north-west of Viterbo...

 extends upward on the northeast shore, with Orvieto

Orvieto

Orvieto is a city and comune in Province of Terni, southwestern Umbria, Italy situated on the flat summit of a large butte of volcanic tuff...

 14 km (8.7 mi) further to the northeast, at the edge of the volcanic region. On the southeast of the lake is Montefiascone

Montefiascone

Montefiascone is a town and comune of the province of Viterbo, Italy, located on a hill on the southeast side of Lake Bolsena, 95 km north of GRA .-History:...

 at an elevation of 633 m (2,076.8 ft), up on the ridge of Montefiascone caldera. To the south of the lake is Marta, on the right bank of the Marta River, sole effluent of the lake. The shore there is straight and developed. Elevations are within 100 m (328.1 ft) of the lake. Next to Marta are Valentano

Valentano

thumb|250px|View of Valentano.Valentano is a town and comune of the province of Viterbo, in the Lazio region of central Italy. It is 33 km from the provincial capital, Viterbo.left|thumb|220px|Rocca Farnese in Valentano....

 and Capodimonte

Capodimonte

Capodimonte is a comune in the Province of Viterbo in the Italian region Lazio, located about 90 km northwest of Rome and about 20 km northwest of Viterbo. It is on the southwestern shore of Lake Bolsena...

, the latter being built on and around nearly the only headland on the lake, which forms a protective harbor. About 15 km (9.3 mi) to the south are Tuscania

Tuscania

Tuscania is a town and comune in the province of Viterbo, Lazio Region, Italy. Until the late 19th century the town was known as Toscanella.-Ancient times:...

 and Viterbo

Viterbo

See also Viterbo, Texas and Viterbo UniversityViterbo is an ancient city and comune in the Lazio region of central Italy, the capital of the province of Viterbo. It is approximately 80 driving / 80 walking kilometers north of GRA on the Via Cassia, and it is surrounded by the Monti Cimini and...

, the latter being the regional capital.

From Valentano

Valentano

thumb|250px|View of Valentano.Valentano is a town and comune of the province of Viterbo, in the Lazio region of central Italy. It is 33 km from the provincial capital, Viterbo.left|thumb|220px|Rocca Farnese in Valentano....

 north is the Latera caldera, a shallow crater perhaps half the size of Lake Bolsena, with Lake Mezzano

Lake Mezzano

Lake Mezzano is a small crater lake of central Italy, of volcanic origin, which was formed 400,000 years ago.The lake has a circular shape typical of crater lakes...

 (usually too small for the map) at the western end. On its north rim is Latera

Latera

Latera is a small town and comune in the Province of Viterbo, Italy.Situated near Bolsena Lake and Mezzano Lake, is important for volcanic underground activity near the town centre. It has a small rock with a medieval palace by Farnese family, surrounded by medieval stone houses.-History:Latera and...

. The floor of the caldera is mainly agricultural although the uncultivable rocky lava flows have been left forested. Although the hills on the west side of Lake Bolsena are only slightly higher than those on the south, the terrain is somewhat too rough for settlement. Fields extend as far as they can into v-shaped valleys and there is no flat shore.

The hills to the north loom over the lake. At their western edge are Grotte di Castro

Grotte di Castro

Grotte di Castro is a comune in the Province of Viterbo in the Italian region Latium, located about 100 km northwest of Rome and about 35 km northwest of Viterbo.-References:...

 and Gradoli

Gradoli

Gradoli is a comune in the Province of Viterbo in the Italian region Latium, located about 100 km northwest of Rome and about 35 km northwest of Viterbo....

.

Geology

Lake Bolsena is at the center of the Vulsinii (or Vulsino) Volcanic District of the Roman Comagmatic Region.

Bisentina

With an area of 17 ha (42 acre), Bisentina is the largest island, and is accessible via a ferry service from Capodimonte. On the island are groves of evergreen oaks, Italian gardens, and various monuments: the church of Saint James and Saint Christopher

Saint Christopher

.Saint Christopher is a saint venerated by Roman Catholics and Orthodox Christians, listed as a martyr killed in the reign of the 3rd century Roman Emperor Decius or alternatively under the Roman Emperor Maximinus II Dacian...

 with its cupola

Cupola

In architecture, a cupola is a small, most-often dome-like, structure on top of a building. Often used to provide a lookout or to admit light and air, it usually crowns a larger roof or dome....

 built by the architect

Architect

An architect is a person trained in the planning, design and oversight of the construction of buildings. To practice architecture means to offer or render services in connection with the design and construction of a building, or group of buildings and the space within the site surrounding the...

 Jacopo Barozzi da Vignola; the Franciscan convent

Convent

A convent is either a community of priests, religious brothers, religious sisters, or nuns, or the building used by the community, particularly in the Roman Catholic Church and in the Anglican Communion...

; the Rocchina, a small temple dedicated to Saint Catherine

Catherine of Alexandria

Saint Catherine of Alexandria, also known as Saint Catherine of the Wheel and The Great Martyr Saint Catherine is, according to tradition, a Christian saint and virgin, who was martyred in the early 4th century at the hands of the pagan emperor Maxentius...

. The latter was constructed in an octagonal floorplan by Antonio da Sangallo

Antonio da Sangallo

Antonio da Sangallo may refer to:* Antonio da Sangallo the Elder , Florentine architect* Antonio da Sangallo the Younger , , Florentine architect and the Elder's nephew...

, over an Etruscan colombarium previously erected on a rocky outcrop on the lake. Another monument, the chapel

Chapel

A chapel is a building used by Christians as a place of fellowship and worship. It may be part of a larger structure or complex, such as a church, college, hospital, palace, prison or funeral home, located on board a military or commercial ship, or it may be an entirely free-standing building,...

 of the Crucifix

Crucifix

A crucifix is an independent image of Jesus on the cross with a representation of Jesus' body, referred to in English as the corpus , as distinct from a cross with no body....

, contains fresco

Fresco

Fresco is any of several related mural painting types, executed on plaster on walls or ceilings. The word fresco comes from the Greek word affresca which derives from the Latin word for "fresh". Frescoes first developed in the ancient world and continued to be popular through the Renaissance...

s of the fifth century. The Malta dei Papi, a former prison

Prison

A prison is a place in which people are physically confined and, usually, deprived of a range of personal freedoms. Imprisonment or incarceration is a legal penalty that may be imposed by the state for the commission of a crime...

 for ecclesiastics found guilty of heresy

Heresy

Heresy is a controversial or novel change to a system of beliefs, especially a religion, that conflicts with established dogma. It is distinct from apostasy, which is the formal denunciation of one's religion, principles or cause, and blasphemy, which is irreverence toward religion...

, was shaped from a small cave with a trapdoor placed at a height of 20 m (65.6 ft).

The Etruscans and the Romans

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 left few traces of their stay on the island. In the 9th century it provided refuge from the incursions of the Saracen

Saracen

Saracen was a term used by the ancient Romans to refer to a people who lived in desert areas in and around the Roman province of Arabia, and who were distinguished from Arabs. In Europe during the Middle Ages the term was expanded to include Arabs, and then all who professed the religion of Islam...

s.

About 1250, it became the property of the lord of Bisenzio, who abandoned it and burned it following disagreements with the inhabitants of the island. In 1261, Urban IV reconquered it. The island was destroyed again in 1333 by Louis IV of Bavaria, accused of heresy and excommunicated by the pope. The property of the Farnese family from 1400 onwards, it had a period of prosperity and was visited by many popes. In 1635, it was governed by Odoardo Farnese

Odoardo Farnese

Odoardo Farnese was Duke of Parma and Piacenza from 1622 to 1646.-Biography:Odoardo was the sole legitimate son of Ranuccio I Farnese and Margherita Aldobrandini...

, duke of Castro

Castro (city)

Castro was an ancient city on the west side of Lake Bolsena in the present-day comune of Ischia di Castro, northern Lazio, Italy. It was destroyed at the conclusion of the Wars of Castro in the 17th century.-Early history:...

, who entered into conflict with the Church, resulting in the total destruction of Castro. The two islands returned to the Church's control but were soon ceded again. The princess Beatrice Spada Potenziani, wife of the duke Fieschi Ravaschieri, is the current owner.

Martana

Located opposite the town of Marta, the island of Martana is reputed to have once guarded the relic

Relic

In religion, a relic is a part of the body of a saint or a venerated person, or else another type of ancient religious object, carefully preserved for purposes of veneration or as a tangible memorial...

s of Saint Christine to keep them from falling into the hands of the barbarian

Barbarian

Barbarian and savage are terms used to refer to a person who is perceived to be uncivilized. The word is often used either in a general reference to a member of a nation or ethnos, typically a tribal society as seen by an urban civilization either viewed as inferior, or admired as a noble savage...

s. Later, it is said that, during the dominion of the Goths

Goths

The Goths were an East Germanic tribe of Scandinavian origin whose two branches, the Visigoths and the Ostrogoths, played an important role in the fall of the Roman Empire and the emergence of Medieval Europe....

, the Gothic queen Amalasuntha

Amalasuntha

Amalasuntha was a queen of the Ostrogoths from 526 to 534....

 was assassinated there.

The island is currently private property and no visitors are permitted.

Marta outlet

The emissary

Emissary (hydraulics)

An emissary is a channel, natural or artificial, by which an outlet is formed to carry off any stagnant body of water...

 Marta, which leaves Lake Bolsena to the east of the community of Marta, is a river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 emptying into the Tyrrhenian Sea

Tyrrhenian Sea

The Tyrrhenian Sea is part of the Mediterranean Sea off the western coast of Italy.-Geography:The sea is bounded by Corsica and Sardinia , Tuscany, Lazio, Campania, Basilicata and Calabria and Sicily ....

. After passing through Marta, Tuscania and Tarquinia

Tarquinia

Tarquinia, formerly Corneto and in Antiquity Tarquinii, is an ancient city in the province of Viterbo, Lazio, Italy.- History :Tarquinii is said to have been already a flourishing city when Demaratus of Corinth brought in Greek workmen...

, it reaches the sea in the area of the lido of Tarquinia. There between the mouth of Marta and that of Mignone was created the natural reservoir

Natural reservoir

Natural reservoir or nidus, refers to the long-term host of the pathogen of an infectious disease. It is often the case that hosts do not get the disease carried by the pathogen or it is carried as a subclinical infection and so asymptomatic and non-lethal...

 "Saltworks of Tarquinia".

Comuni bordering the lake

The following comuni

Comune

In Italy, the comune is the basic administrative division, and may be properly approximated in casual speech by the English word township or municipality.-Importance and function:...

are situated on the shore of Lake Bolsena:

• Bolsena
  Bolsena
  Bolsena is a town and comune of Italy, in the province of Viterbo in northern Lazio on the eastern shore of Lake Bolsena. It is 10 km north-north west of Montefiascone and 36 km north-west of Viterbo...
  
  
• Montefiascone
  Montefiascone
  Montefiascone is a town and comune of the province of Viterbo, Italy, located on a hill on the southeast side of Lake Bolsena, 95 km north of GRA .-History:...
  
  
• Marta
• Capodimonte
• Valentano
  Valentano
  thumb|250px|View of Valentano.Valentano is a town and comune of the province of Viterbo, in the Lazio region of central Italy. It is 33 km from the provincial capital, Viterbo.left|thumb|220px|Rocca Farnese in Valentano....
  
  
• Gradoli
  Gradoli
  Gradoli is a comune in the Province of Viterbo in the Italian region Latium, located about 100 km northwest of Rome and about 35 km northwest of Viterbo....
  
  
• Grotte di Castro
  Grotte di Castro
  Grotte di Castro is a comune in the Province of Viterbo in the Italian region Latium, located about 100 km northwest of Rome and about 35 km northwest of Viterbo.-References:...
  
  
• San Lorenzo Nuovo
  San Lorenzo Nuovo
  San Lorenzo Nuovo is a small town and comune in the province of Viterbo, in the Latium region of Italy. It is an important agricultural center for potatoes, olive oil, garlic, onions, cereals and grapes. A second source of revenue is tourism.-Geography:...
  
  

Each has a designated length of beach for summer swimming. Some of these have facilities such as cafes, restaurants and boat hire.

Other nearby towns are Sorano

Sorano

Sorano is a town and comune in the province of Grosseto, southern Tuscany .It as an ancient medieval hill town hanging from a tuff stone over the Lente River.thumb|220px|left|A view of Sorano.-History:...

, Pitigliano

Pitigliano

Pitigliano is an Italian town and comune of province of Grosseto in the Maremma area of Tuscany. The town stands on an abrupt tuff butte high above the Olpeta, the Fiora and the Lente rivers.-History:...

, Acquapendente

Acquapendente

Acquapendente is a city and comune in the province of Viterbo, in Lazio . Acquapendente is an important centre for the agricultural production of vegetables and wine, and has a tradition of pottery craftmanship.-History:...

 and Orvieto

Orvieto

Orvieto is a city and comune in Province of Terni, southwestern Umbria, Italy situated on the flat summit of a large butte of volcanic tuff...

, with Onano to the northwest.

External links