While it is possible, in principle, for an individual to have her or his own unique religious beliefs and to engage in her or his own religious practices without necessarily associating with other religious believers, most religions have some form of social organization. Especially in some small-scale societies, the social institutions in which religious practices take place may be identical with those in which other activities, such as economic activities, take place. In other societies, there are specialized religious institutions, such as organized denominations in Christianity, monastic orders in Buddhism, and congregations of the faithful in Judaism or Islam. Even within the same broad religious tradition, such as Christianity, there may be more than one model of religious organization -- ranging, for example, from the formalized and hierarchical system of the Church of Rome to the more egalitarian and informal system in some Protestant churches. Many, but not all, religions have specialized religious functionaries such as gurus, monks, priests, imams, 'ulema, rabbis, ministers, shamans, etc.