While women rulers have led great empires as hereditary monarchs since ancient times, the first appointed female head of state didn't take office until 1960, when Sirivamo Bandaranaike of Sri Lanka became the world's first female elected Premier, serving as head of the government. In 1974, Isabel Peron was secretly sworn in as President of Argentina following the death of her husband, Argentinian strongman Juan Peron, becoming the first woman in history to hold the top position of power.
Since then, it's become more and more common for women to be elected as the leaders of their nations. Many of the most powerful countries on earth, including Germany, India, Brazil, South Korea, Israel, Chile, and the United Kingdom have elected or appointed women as their heads of state. These women presidents and prime ministers have had command of nuclear weapons, powerful economies, vast populations, and - most importantly - the respect of their people.
Here is the complete list of current presidents or heads of government who are women.