Like many of the other Fallas events, the Nit del Foc has undergone various changes and it only started taking its current form in the last decades of the 20th century.
First Nit del Foc
At this point the Nit del Foc was celebrated as part of the Semana Fallera and it resembled a nighttime Mascletà (made up mostly of firecrackers and not as many fireworks and lights).
Castillo de Fuegos
The display takes the form of a proper Castillo de Fuegos Artificiales - an elaborate firework display - and not just a Mascletà Nocturna.
An article documents that the Nit del Foc, which took place on the 16th of March (as was customary at the time), was organised by Vicente Caballer. The document mentions that the display was so grand that it was expected to break some glass windows in the city.
Celebration on the current date
It was only in ‘87 that the Nit del Foc started being celebrated on the same day as it currently does: the night between the 18th and the 19th. Back then, the display was still not as complex as it is nowadays, thanks to the advancements of technology.