The Great Fire of Rome, AD 64, may have been the beginning of the end for the emperor Nero. Whether it was deliberately set by Nero's minions or started accidentally, is still hotly debated. (Of course, this was not the only big fire in Ancient Rome and received notoriety only because of the personality of Nero and the ancient historians, see texts below.) It was the subject of Secrets of the Dead: The Great Fire of Rome at PBS.
Wikipedia (handle with care) has a nice coverage.
Anthony Burgess, in our current read The Kingdom of the Wicked has a lot to draw on. His marvelous description (page 387 ff) borders on the epic.
The main sources are
After this Nero set his heart on accomplishing what had doubtless always been his desire, namely to make an end of the whole city and realm during his lifetime. At all events, he, like others before him, used to call Priam wonderfully fortunate in that he had seen his country and his throne destroyed together. Accordingly he secretly sent out men who pretended to be drunk or engaged in other kinds of mischief, and caused them at first to set fire to one or two or even several buildings in different parts of the city, so that people were at their wits' end, not being able to find any beginning of the trouble nor to put an end to it, though they constantly were aware of many strange sights and sounds.
[When] someone in a general conversation said:
“When I am dead, be earth consumed by fire,”
he rejoined “Nay, rather while I live,” and his action was wholly in accord. For under cover of displeasure at the ugliness of the old buildings and the narrow, crooked streets, he set fire to the city so openly that several ex-consuls did not venture to lay hands on his chamberlains although they caught them on their estates with tow and fire-brands, while some granaries near the Golden House, whose room he particularly desired, were demolished by engines of war and then set on fire, because their walls were of stone. For six days and seven nights destruction raged, while the people were driven for shelter to monuments and tombs. At that time, besides an immense number of dwellings, the houses of leaders of old were burned, still adorned with trophies of victory, and the temples of the gods vowed and dedicated by the kings and later in the Punic and Gallic wars, and whatever else interesting and noteworthy had survived from antiquity. Viewing the conflagration from the tower of Maecenas and exulting, as he said, in “the beauty of the flames,” he sang the whole of the “Sack of Ilium,” in his regular stage costume. Furthermore, to gain from this calamity too all the spoil and booty possible, while promising the removal of the debris and dead bodies free of cost he allowed no one to approach the ruins of his own property; and from the contributions which he not only received, but even demanded, he nearly bankrupted the provinces and exhausted the resources of individuals.
… A disaster followed, whether accidental or treacherously contrived by the emperor, is uncertain, as authors have given both accounts, worse, however, and more dreadful than any which have ever happened to this city by the violence of fire. It had its beginning in that part of the circus which adjoins the Palatine and Caelian hills, where, amid the shops containing inflammable wares, the conflagration both broke out and instantly became so fierce and so rapid from the wind that it seized in its grasp the entire length of the circus. For here there were no houses fenced in by solid masonry, or temples surrounded by walls, or any other obstacle to interpose delay. The blaze in its fury ran first through the level portions of the city, then rising to the hills, while it again devastated every place below them, it outstripped all preventive measures; so rapid was the mischief and so completely at its mercy the city, with those narrow winding passages and irregular streets, which characterised old Rome. read all
One thing is for sure, Nero never fiddled, while Rome burned...
JSTOR, for those with access, has a 1909 article The Burning of Rome under Nero, Ch. Hülsen, American Journal of Archaeology Vol. 13, No. 1 (Jan., 1909), pp. 45-48, discussing how the fire may have started.
The above image depicts The burning of Rome, Robert Hubert (1733-1808), Musée André Malraux, Le Havre, France.