The 18th of Tir Anniversary and Remembrance

Iranian Student Protests of July, 1999 (Also known as 18th of Tir and Kuye Daneshgah Disaster in Iran) (7-13 July) were the "worst", most widespread and violent public protests in Iran, since the early years of the Iranian Revolution.

They began on July 8 with peaceful demonstrations in Tehran against the closure of the reformist newspaper, Salam. This was followed by an attack on a student dormitory that night by vigilantes and riot police in which a student was killed. This in turn sparked six days of demonstrations and rioting in which at least three more people were killed and more than 200 injured.

Following the Iran student riots in 1999, more than seventy students disappeared. In addition, to an estimated 1,200-1,400 detained, the "whereabouts and condition" of five students named by Human Rights Watch remained unknown, but are believed to be detained by Islamic authorities.
http://en.wikipedia.org/wiki/Iran_student_protests,_July_1999