Monthly meetings are the basic unit of worship in the Religious Society of Friends (Quakers), usually equivalent organizationally to a single church congregation in Protestant denominations. Monthly meetings are charged with the bulk of pastoral care of their associated congregants. Quaker organizational structure is complicated and varies from place to place, but in many cases, Monthly meetings are grouped for various purposes into Quarterly meetings, which themselves are grouped into Yearly meetings. In places where Quakers are few, there may be no Quarterly meeting.