Shab-e-Yalda (Yalda Night) also known as Shab-e Chelleh is one of the most ancient Persian festivals annually celebrated on the longest and darkest night of the year by Iranians all around the world. It is a winter solstice celebration that corresponds to the night of December 20 or 21.

Yalda means birth and it refers to the birth of Mitra; the mythological goddess of light. Since days get longer and nights get shorter in winter, Iranians celebrate the last night of autumn as the renewal of the sun and the victory of light over darkness.

On Yalda Night, Iranians gather together usually at the home of grandparents or the elderly to pass the longest night of the year happily by making good wishes, and talking and laughing all together to give a warm welcome to winter, and a nice farewell to autumn. In addition, storytelling, reading poetry especially poems of Hafiz, eating nuts and fruits such as watermelon and pomegranate are among the rituals observed on this night. Apart from being delicious, the fruits of Yalda Night are symbolic as well.