The most important holiday in iran is "Nouruz" which is the celebration of the Iranian new year. Festivities take place over 12 days and it includes cleaning the house which allways starts one week before nouruz, buying variety of sweets,fruits and nuts to entertain the guests. During this 12 days all the relatives and friends visit each other by going to each other's home and typically, young people visit their elders first, then the elders return their visit. The other Iranian festival is "sizde bedar" which is celebrated on the 13th day of nouruz and it is a kind of nature day. People gather together and go outdoors to be in the nature. We make a campfire and then we can make some food like "kabab" made out of meat or chicken on that. The other Iranian ancient festival is "char shanbe suri" which is celebrated on the night before the last Wednesday of the year. People make bonfires in the streets or in the yards and jump over them and young adults light fire crackers and the city will be full of the noises of these carckers during that night and actually the way nowadays it is celebrated is quite different from what it used to be ancient times. The last Iranian holiday is called "yalda night" which is celebrated during the longest night of year and people gather and eat watermelon pomegranate nuts and sweets..these 4 traditional holidays remained popular since ancient times , befor Islam came to Iran and they actually go back the ancient zoroastrian faith , a religion that was practiced in ancient Persia. We have more holidays which are related to islam too but these ones are the most popular and joyful ones among Iranians.