Norouz marks the first day of spring and the beginning of the Iranian year and It is celebrated on March 21st. The term Norouz first appeared in Persian records in the second century AD, but it was also an important day during the Achaemenid times (c. 648-330 AD), where kings from different nations under Persian empire used to bring gifts to the emperor (Shahanshah) of Persia on Norouz.
Tradition dates Noruz as far back as 15,000 years ago -- before the last ice age. The mythical Persian King Jamshid (Yima or Yama of the Indo-Iranian lore) symbolizes the transition of the Indo-Iranians from animal hunting to animal husbandry and a more settled life in human history. Seasons played a vital part then. Everything depended on the four seasons. After a severe winter, the beginning of spring was a great occasion with mother nature rising up in a green robe of colorful flowers and the cattle delivering their young. It was the dawn of abundance. Jamshid is said to be the person who introduced Noruz celebrations.
Norouz has been celebrated for at least 3000 years and is deeply rooted in the rituals and traditions of the Zoroastrian religion. Today, the festival of Norouz is celebrated in many countries that were territories of, or influenced by, the Persian Empire.
In most countries, the greeting that accompanies the festival is Ayd-e Norouz Mobārak (mubarak: felicitations) in Persian. In Iran, preparations for Norouz begin in Esfand (or Espand), the last month of winter in the Persian solar calendar.
Typically, on the first day of Norouz, family members gather around the table, with the Haft Seen on the table or set next to it, and await the exact moment of the arrival of the spring. At that time gifts are exchanged. Later in the day, the first house visits are paid to the most senior family members.

Haft Sîn or the seven 'S's is a major tradition of Norouz. The haft sin table includes seven items specific starting with the letter S or Sîn in Persian alphabet). The items symbolically correspond to seven creations and holy immortals protecting them. Originally called Haft Chin, the Haft Sin has evolved over time, but has kept its symbolism. Traditionally, families attempt to set as beautiful a Haft Sîn table as they can, as it is not only of traditional and spiritual value, but also noticed by visitors during Norouzi visitations and is a reflection of their good taste.
The Haft Sin items are:

•sabzeh - wheat, barley or lentil sprouts growing in a dish - symbolizing rebirth
•samanu - a sweet pudding made from wheat germ - symbolizing affluence
•senjed - the dried fruit of the oleaster tree - symbolizing love
•sîr - garlic - symbolizing medicine
•sîb - apples, - symbolizing beauty and health
•somaq - sumac berries - symbolizing (the color of) sunrise
•serkeh - vinegar - symbolizing age and patience