Shab e Chelleh

(Chelle Night; It is also known as Yalda Night)

Yalda night is the longest night of the year (simultaneously with the last hours of the last day of Azar and the early hours of the first day of Dey, according to the Iranian calendar and equal to December 20/21), which is celebrated in Greater Iran.Yalda night is actually the winter solstice and has been officially added to the calendar of Iranian people since 502 BC. Ancient Iranians believed that in this night, light overcomes darkness.
On this night, families gather together. People eat sweets, nuts,fruits (especially pomegranates, watermelons, grapes and persimmons) and pumpkin on Yalda night. Red color, pomegranate and watermelon are the symbols of this ancient festival.

more info

Yalda Night