Iranians flocked to parks and orchards to mark Sizdeh Bedar, an ancient festival that predates Islam and goes back thousands of years to the time when Zoroastrianism was the predominant religion of Persia.
Iran's hard-line ruling clerics have discouraged many pre-Islamic rituals, but they've been unable to put Iranians off the Persian New Year, or Nowruz, and its ending celebration of Sizdeh Bedar.
The festival falls on the thirteenth day of Nowruz _ Sizdeh is 13 and Bedar means "passing" in Persian.
It is believed to be bad luck to stay indoors for the holiday, so families and friends traditionally head outdoors for an elaborate picnic lunch.
The festival has several traditions. Iranians throw trays of sprouted seeds that have been sitting on their Nowruz tables into water representing happy life. Young and old alike tie blades of grass or flowers together in the hope the New Year will be filled with happiness and prosperity. Young girls usually make wishes to get married as they tie the blades of grass.
Nowruz is also celebrated in parts of Turkey, Azerbaijan, Turkmenistan, Tajikistan, Kyrgyzstan and Afghanistan.