Sizdah Bedar سیزدهبدر , is an Iranian festival held annually on the thirteenth day of Persian New Year, Farvardin (the first month of Persian calendar). During this day people spend time outdoors in a form of picnic with family and friends.
As many other cultures believe, the number 13 is considered to bring bad luck and Perisan culture is not an exception. People do not want to keep the bad luck at home, therefore, they go out to a picnic.
Sizdah Bedar is an official holiday in Iran, known as the Nature Day.
Picnic aside, unmarried girls tie the leaves of greenery, usually the Sabzeh (from Haft Seen table) and then throw it in the water, hoping they will get marries soon.