The Letters of
Pliny the Younger

With all the Details Expected
Eruption of Mount Vesuvius in 79 AD
one of the most famous volcanic eruptions in history
Of the many eruptions of Mount Vesuvius, a major stratovolcano in southern Italy, the most famous is its eruption in 79 AD, which was one of the deadliest in European history.
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At the time, the region was a part of the Roman Empire, and several Roman cities were obliterated and buried underneath massive pyroclastic surges and ashfall deposits, the best known being Pompeii and Herculaneum.
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The only surviving eyewitness account of the event consists of two letters by Pliny the Younger, who was 17 at the time of the eruption, to the historian Tacitus and written some 25 years after the event. Observing the first volcanic activity from Misenum across the Bay of Naples from the volcano, approximately 29 kilometres (18 mi) away, Pliny the Elder (Pliny the Younger's uncle) launched a rescue fleet and went himself to the rescue of a personal friend.
Wikipedia

The Passion of Pliny the Elder
"Pliny the Younger wrote a lot about his uncle and adoptive father, Pliny the Elder. And the younger Pliny's good friend Tacitus was fascinated by his uncle's heroic death. So he wrote Pliny a letter asking him to tell him all he knew about the circumstances of the elder Pliny's death and how he bore it and how he acted in his final days. Tacitus wanted to include something on it in the history he was writing, but it's obvious he really just wanted to hear about this remarkable and heroic story. Who wouldn't? Human curiosity is universal, and something like this could not just be let aside as of no interest. The circumstances of his death, after all, were 'so memorable that it likely to make his name live forever'. Much like Jesus, according to some.
Glad to answer Tacitus, the younger Pliny wrote him a letter containing an extensive eyewitness account of all he saw and knew about his father's death, in around 1,500 words. For comparison, Paul's letter to the Galatians, one of his shortest, contains around 3,000 words; Romans, nearly 10,000... Overall we have around 20,000 words from Paul. But in Pliny's mere 1,500 words we learn that his father died from respiratory failure after breathing the ashfall of Mount Vesuvius in his attempt to investigate the disaster and rescue survivors as commander of the Roman naval fleet stationed nearby. Pliny relates as much detail as he was witness to and those present informed him of. Pliny's response peaked Tacitus's curiosity and questions even more, and he wrote again, asking what the younger Pliny himself did in the days immediately following that tragedy. Pliny again obliged him with an account of that in a following letter. As Pliny says,'the letter which you asked me to write on my uncle's death has made you eager to hear about the terrors and also the hazards I had to face' afterward.
This is the kind of exchange of letters we should expect to have from the earliest Christians. Not necessarily in every respect, but surely something like it. Curiosity, the burning desire to know, to have firsthand accounts, to have specific questions answered and desires for knowledge satisfied, would dominate every congregation under Paul and beyond, most especially in respect to the Son of God and Savior of the Universe whose deeds and speeches and death were (for them) the most important in all of history. The same burning desires exhibited by Tacitus and eagerly satisfied by Pliny would have been multiplied a hundredfold in the two decades of Paul's mission, given the number of Christians and distant churches there were by then, spanning three continents. For not even one person to have ever exhibited this interest in writing nor for any to have so satisfied it is bizarre. Saying this all went on in person is simply insufficient to answer the point: if everything was being resolved in person, Paul would never have written a single letter; nor would his congregations have so often written him letters requesting he write to satisfy their questions -which for some reason always concerned only doctrine and rules of conduct, never the far more interesting subject of how the Son of God lived and died. On the other matters Paul was compelled to write tens of thousands of words. If he had to write so much on those issues, how is it possible no one ever asked for or wrote even one word on the more obvious and burning issues of the facts of Jesus' life and death?"
R. Carrier, On the Historicity of Jesus p.510-512
Pliny Letter 6.16 and 6.20 or the full Book 6 Pliny the Younger : Letters or at macroevolution.net