Countries with a sovereign monarchy are the United Kingdom, Sweden, Norway, Denmark, The Netherlands, Spain, Belgium, Monaco, Thailand, Japan, Morocco, and Vatican City. Most of the monarchies are hereditary, which means they are passed down from one family to another, usually from father to son, but not in every situation.
The United Kingdom, and fifteen Commonwealth countries, for example, are headed by Queen Elizabeth II. These commonwealth countries were once a part of the vast empire that Britain ruled in the 19th and 20th centuries. Elizabeth is Queen because her uncle, King Edward VIII abdicated the throne. Other countries are both elective and hereditary.