As of 2015, the countries that are ruled by a king or a queen include the United Kingdom, which is ruled by Queen Elizabeth II. Other countries are Denmark ruled by Queen Margrethe II, Norway ruled by King Harald V and Sweden ruled by King Carl XVI Gustav.
Belgium is ruled by King Philippe, while Spain's king is Felipe VI. Lesotho is ruled by King Letsie III and Swaziland by King Mswati III. Japan's emperor is Akihito, the king of Tonga is Tupou VI, and the king of the Netherlands is Willem-Alexander.
The king of Jordan is Abdullah II. The king of Saudi Arabia is also Abdullah, and the king of Bahrain is Hamad bin Isa al-Khalifa. Morocco's king is Mohammed VI and Cambodia's king is Norodom Sihamoni. The king of Bhutan is Jigme Khesar Namgyel Wangchuck.
The world's longest reigning monarch is King Bhumibol Adulyadej of Thailand, who has been reigning since 1946. The second longest reigning monarch is Queen Elizabeth II, who came to the throne upon the death of her father, George VI, in 1952. Queen Elizabeth's kingdom is the largest in terms of area and population, as it stretches from the British Isles to Canada to Australia, the Caribbean and Polynesia.