Sizdah Bedar

Sizdah is the Persian term for thirteen. The 13th day of the first month of the Iranian New Year is called Sizdah Be-dar and Nature Day. On this day marking the end of the New Year holidays, people prepare a large picnic and stay outdoors to enjoy a day of sports and fun with friends and relatives.
On Sizdah Bedar, many big cities in Iran look empty and unpopulated.
At the end of their picnics people throw away the green sprouts, known as Sabzeh (from the traditional Haft Seen table that they prepared for the first day of New Year).
More pictures: 1, 2, 3