Diwali is a light festival in India that is celebrated at least well over a 1000 years.
In the early 15th century, the Venetian merchant and traveller Niccolo de Conti visited India and wrote about the festival:
'On another of these festivals they fix up within their temples, and on the outside of the roofs, an innumerable number of oil lamps.'
The lights symbolize the triumph of light over darkness, good over evil.
Tradition links the festival to the great Indian epic the Ramayana (dating perhaps between 700-400 BC), although other religious groups have come to celebrate the festival for different reasons. In the Ramayana, diwali marks the day that Rama returned to the city Ayodhya after a period of exile and defeated the army of the demon king Ravana.
I wish everyone a happy Diwali.
"The Great World History Book"