By David Willey
BBC News, Rome
At first sight, it looked like a recreation of the legendary burning of the city of Rome under the reign of the Emperor Nero in 64AD.
There were no reported deaths or injuries following the blaze
Flames suddenly leapt 30 and 40 metres high into the hot and humid summer-night air from a storage facility at Cinecitta (Film City).
These are the studios on the southern outskirts of the Italian capital where many epic films about ancient Rome have been shot.
Quo Vadis (1949) was made here, as was Ben Hur (1958), directed by William Wyler.
Police said the store where the fire started contained large quantities of highly inflammable synthetic materials.
The fire broke out on the set of Rome, a completed joint HBO and BBC mini-series on the ancient empire.
The main set, which also includes a mock Roman forum, was not destroyed, but some other parts were heavily damaged, HBO spokeswoman Mara Mikialian said.
She added that shooting of the second series of Rome had been already completed.
Part of a sprawling film set representing the ancient city went up in smoke before firefighters could douse the blaze.
Rome's fire chief feared the flames would spread to the densely-populated neighbourhood next to the spacious studio compound.
The studios are based a few kilometres from the Italian capital
It took three hours to bring the blaze under control.
But according to the head of the studios, Francesco Carducci Artenisio, only a small section of the Cinecitta complex was affected by the fire and future productions will not be compromised.
The cause of the fire is believed to have been an electrical short circuit, although investigators have not yet entirely ruled out the possibility of arson.
Cinecitta was the brainchild of Italy's Fascist dictator Benito Mussolini. It was to be the biggest film studio complex in Europe.
He personally opened the studios - built in what was then open countryside, nine kilometres from the city centre - in April 1937.
The original complex contained 73 buildings and 16 sound stages set amid acres of gardens.
The fire began in a store which had been used for film sets
Mussolini also set up his propaganda documentary and news film unit here.
Today it contains one of the most valuable film archives of the events of the 1920s and 1930s.
In Cinecitta's first six years of existence, more than 300 full-length feature films were produced, under the direction of such famous film-makers as Roberto Rosellini, Vittorio de Sica and Luchino Visconti.
Pier Paolo Pasolini and Federico Fellini also worked at Cinecitta.
In the 1950s Cinecitta was dubbed "Hollywood on the Tiber".
Dame Elizabeth Taylor and Richard Burton were among the Hollywood stars who liked to film in Rome.
But by the 1990s cheaper locations in more exotic countries attracted Hollywood film-makers more, and Cinecitta fell on hard times.
More recently the studios had an expensive makeover to enable them to offer facilities for smaller-budget TV productions.
But big-budget films do continue to be produced in Rome - American director Martin Scorsese came to Cinecitta to shoot Gangs of New York, starring Daniel Day-Lewis and Leonardo DiCaprio.