Pliny the Younger in the context of "Indica (Megasthenes)"

The Natural History (Latin: Naturalis historia) is a Latin work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the Natural History compiles information gleaned from other ancient authors. Despite the work's title, its subject area is not limited to what is today understood by natural history; Pliny himself defines his scope as "the natural world, or life". It is encyclopaedic in scope, but its structure is not like that of a modern encyclopaedia. It is the only work by Pliny to have survived, and the last that he published. He published the first 10 books in AD 77, but had not made a final revision of the remainder at the time of his death during the AD 79 eruption of Vesuvius. The rest was published posthumously by Pliny's nephew, Pliny the Younger.

The work is divided into 37 books, organised into 10 volumes. These cover topics including astronomy, mathematics, geography, ethnography, anthropology, human physiology, zoology, botany, agriculture, horticulture, pharmacology, mining, mineralogy, sculpture, art, and precious stones.

Volcanic lightning is an electrical discharge caused by a volcanic eruption rather than from an ordinary thunderstorm. Volcanic lightning arises from colliding, fragmenting particles of volcanic ash (and sometimes ice), which generate static electricity within the volcanic plume, leading to the name dirty thunderstorm. Moist convection currents and ice formation also drive the eruption plume dynamics and can trigger volcanic lightning. Unlike ordinary thunderstorms, volcanic lightning can also occur when there are no ice crystals in the ash cloud.

The earliest recorded observations of volcanic lightning are from Pliny the Younger, describing the eruption of Mount Vesuvius in 79 AD, "There was a most intense darkness rendered more appalling by the fitful gleam of torches at intervals obscured by the transient blaze of lightning." The first studies of volcanic lightning were also conducted at Mount Vesuvius by Luigi Palmieri who observed the eruptions of 1858, 1861, 1868, and 1872 from the Vesuvius Observatory. These eruptions often included lightning activity.

Mount Vesuvius (/vəˈsuːviəs/ və-SOO-vee-əs) is a somma–stratovolcano located on the Gulf of Naples in Campania, Italy, about 9 km (5.6 mi) east of Naples and a short distance from the shore. It is one of several volcanoes forming the Campanian volcanic arc. Vesuvius consists of a large cone partially encircled by the steep rim of a summit caldera, resulting from the collapse of an earlier, much higher structure.

The eruption of Mount Vesuvius in 79 AD destroyed the Roman cities of Pompeii, Herculaneum, Oplontis, Stabiae and other settlements. The eruption ejected a cloud of stones, ash and volcanic gases to a height of 33 km (21 mi), erupting molten rock and pulverized pumice at the rate of 6×10 cubic metres (7.8×10 cu yd) per second. More than 1,000 people are thought to have died in the eruption, though the exact toll is unknown. The only surviving witness account consists of two letters by Pliny the Younger to the historian Tacitus.

Histories (Latin: Historiae) is a Roman historical chronicle by Tacitus. Written c. 100–110, its complete form covered c. 69–96, a period which includes the Year of Four Emperors following the downfall of Nero, as well as the period between the rise of the Flavian dynasty under Vespasian and the death of Domitian. However, the surviving portion of the work only reaches the year 70 and the very beginning of the reign of Vespasian.

Together, the Histories and the Annals amounted to 30 books. Saint Jerome refers to these books explicitly, and about half of them have survived. Although scholars disagree on how to assign the books to each work, traditionally, fourteen are assigned to Histories and sixteen to the Annals. Tacitus' friend Pliny the Younger referred to "your histories" when writing to Tacitus about the earlier work.

Plinian eruptions or Vesuvian eruptions are volcanic eruptions characterized by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.

Plinian eruptions eject columns of volcanic debris and hot gases high into the stratosphere, the second layer of Earth's atmosphere. They eject a large amount of pumice and have powerful, continuous gas-driven eruptions.

In Ancient Roman architecture a cryptoporticus (from Latin crypta and porticus) is a covered corridor or passageway. The usual English is "cryptoportico". The cryptoportico is a semi-subterranean gallery whose vaulting supports portico structures aboveground and which is lit from openings at the tops of its arches.

On sloping sites the open side of a cryptoporticus is often partially at ground level and supports a structure such as a forum or Roman villa, in which case it served as basis villae. It is often vaulted and lit by openings in the vault. In the letters of Pliny the Younger, the term is used as a synonym of crypt. The shade and semi-excavated site of a cryptoportico provided cool and moderated temperatures useful for storage of perishables, while it offered a level and slightly raised podium for the superstructure.