When the 21st century began, the world was made up of almost 200 different countries. Most nations have one of five main types of government.
In a democracy, the government is made for the people, by the people. One example of a democracy is Switzerland.
A republic is a kind of democracy in which voters elect leaders to represent them, and there is also one head of government. In the United States, which is a constitutional republic, that head of government is the president.
Under communism, as in China, most businesses and resources are owned by the state instead of by private citizens. The government gives people certain services, like health care and education.
A monarchy is ruled by royalty, like a king or queen. Some monarchs, like the king of Britain, are heads of state but have limited power over the government. Other monarchs, like the king of Saudi Arabia, are supreme leaders.
In a dictatorship, one person has gained complete power, usually by force. One famous dictator was Fidel Castro, who ruled Cuba from 1959 through 2008.