In many countries the head of the state is the president. For example, in present in USA, in Republic of Moldova, in Romania, in Russia, in France, in Ukraine and others. In other states the head is the king. In Luxembourg, for example, in Japan also, in Canada, in Spain and others, but exist the queen, she also can be the head of the state, like in Great Britain. The shaik was in the past in Arabian Peninsula, but in present some of them are lead by emir, like Saudi Arabia. The tzars were in the past, in Russia, Bulgaria, Serbia and Kievan Rus'.
