The new Iranian year began at 16:15 GMT on Tuesday, coincident with the spring equinox, an astronomical event that marks the start of spring in the northern hemisphere.
Iranian families inside and outside the country gathered together to see in the new year with the ancient festivities of Nowruz.
From time immemorial, Iranians celebrate Nowruz together, irrespective of their age, language, gender, race, ethnicity, or social status.
The word Nowruz itself literally means "new day" in the Persian language and the festivity marks the beginning of the solar year as well as the new year on the Iranian calendar.
On the first day of spring on Farvardin 1, when day and night are around the same length, Iranian families visit their elder relatives and give presents to each other.
Other traditions in Nowruz include cleaning the home, making special foods, and preparing seven symbolic things known as the 'Haft Seen'. These all begin with the letter 'S' (or letter 'Seen' in Persian). The items symbolically correspond to seven creations and holy immortals protecting them. The Haft Seen has evolved over time, but has kept its symbolism.
In 2010, the UN General Assembly established March 21 as the International Day of Nowruz. The UN also celebrates the International Day of Happiness.
The international Nowruz Day was proclaimed at the initiative of several countries that share this holiday, including Iran, Afghanistan, Albania, Azerbaijan, the Former Yugoslav Republic of Macedonia, India, Kazakhstan, Kyrgyzstan, Tajikistan, Turkey and Turkmenistan.