Yalda registered as National Heritage Yalda festival which marks the longest night of the year in the northern hemisphere was officially registered on the national heritage list on Saturday.

Night of Yalda, celebrated on December 21, has great significance in the Iranian calendar.

Yalda, the last night of autumn and the beginning of winter, is observed in every Iranian family here or abroad with ethnic roots to Iran.

On Yalda night members of the family stay together, narrate old stories told by ancestors, play traditional games and eat dried and fresh fruits symbolizing various things.

Pomegranates, placed on top of a fruit basket, are reminders of the cycle of life -- the rebirth and revival of generations.

The purple outer covering of a pomegranate symbolizes "birth" or "dawn" and their bright red seeds the "glow of life."

Watermelons, apples, grapes, sweet melons and persimmon are other special fruits served on Yalda night and all are symbols of freshness, warmth, love, kindness and happiness.

Yalda is a Syriac word meaning birth. Ancient Iranian Mitra- worshipers used the term 'Yalda' specifically with reference to the birth of Mitra.

As the longest night of the year, the Eve of Yalda is also a turning point, after which the days grow longer.

In ancient times it symbolized the triumph of the Sun God over the powers of darkness.

Because Yalda is the longest and darkest night, it has happened to symbolize many things in Persian poetry; separation from a loved one, loneliness and waiting.

After Yalda a transformation takes place -- the waiting is over, light shines and goodness prevails.

Ancient Iranians believed that the dawning of each year is marked with the re-emergence or rebirth of the sun, an event which falls on the first day of the month of Dey in the Iranian calendar (December 21).

On this day, the sun was salvaged from the claws of the devil, which is represented by darkness, and gradually spread its rays all over the world to symbolize the triumph of good over evil.

It is not clear when and how the word Yalda entered the Persian language.

The massive persecution of the early Christians in Rome brought many Christian refugees into the realm of the Sassanid Empire and it is very likely that those Christians introduced and popularized Yalda in Iran.

Gradually Shab-e Yalda and Shab-e Cheleh became synonymous and the two are used interchangeably.

Reading poems of the Iranian poet, Hafez, is one of the most familiar activities on Yalda night.