Popular Islam ranges from informal prayer sessions or Qur'an study to organized cults or orders. Because of the pervasive sexual segregation of Egypt's Islamic society, men and women often practice their religion in different ways. A specifically female religious custom is the Zār, a ceremony for helping women placate spirits who are believed to have possessed them. Women specially trained by their mothers or other women in zar lore organize the ceremonies. A zar organizer holds weekly meetings and employs music and dance to induce ecstatic trances in possessed women. Wealthy women sometimes pay to have private zars conducted in their homes; these zars are more elaborate than public ones, last for several days, and sometimes involve efforts to exorcise spirits. However, while once common, the zar is rarely practiced today, under fire for its perception as a religious heresy.