Shab-e-Yalda (Yalda Night) also known as Shab-e Chelleh is one of the most ancient Persian festivals annually celebrated on December 21 by Iranians all around the world. Yalda is a winter solstice celebration; it is the last night of autumn and the longest night of the year. Yalda means birth and it refers to the birth of Mitra; the mythological goddess of light. Since days get longer and nights to 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 Shab-e-Yalda, people gather in groups of friends or relatives usually at the home of grandparents or the elderly to pass the longest night of the year happily by eating nuts and fruits, reading Hafiz poems, making good wishes, and talking and laughing all together to give a warm welcome to winter, and a felicitous farewell to autumn.