[4] Roman historic records indicate activity of the Vulsini volcano occurred as recently as 104 BC; it has been dormant since then.

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.

In recognition of the donation, the Alberici family was honored with a ceremony three times a year performed by the Bishop of Orvieto.

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.

The lake formed when a circular area collapsed after the depletion of the underlying magmatic chamber that fed the whole volcanic district.

The major calderas of the area are found close to the lake's rim (Latera to the west and Montefiascone to the south east).

With an area of 17 ha (42 acres), Bisentina is the largest island, and is accessible via a ferry service from Capodimonte.

The latter was constructed in an octagonal floorplan by Antonio da Sangallo, over an Etruscan columbarium previously erected on a rocky outcrop on the lake.

The Malta dei Papi, a former prison for ecclesiastics found guilty of heresy, was shaped from a small cave with a trapdoor placed at a height of 20 m (66 ft).

Mysterious in its creation, located under Mount Tabor, the highest point of the island, cited by Dante Alighieri as a life-prison.

"Malta dei Papi is a deep tunnel dug into the tuff at the end of which there is an underground chamber of about 6 meters built around a well, and above which there is a circular opening used to collect water.

The waterproof plaster found on its inside walls reveal that the structure was used as a cistern in Roman Times.

Forgotten after being turned for a long time into a stage of atrocities as a prison for heretics, this chamber became subject of occultist conversation in the late 19th century in Madame Blavatsky’s theosophic society, who considered this place to be one of the secret entrances to the underground kingdom of Agarthi, "the Inaccessible".

Located opposite the town of Marta, the island of Martana is reputed to have once guarded the relics of Saint Christine to keep them from falling into the hands of the barbarians.

The following comuni are situated on the shore of Lake Bolsena: Each has a designated length of beach for summer swimming.