Spain's King Juan Carlos is planning to abdicate in favor of his son, Crown Prince Felipe, after many decades on the throne. Juan Carlos represents an ancient institution that retains tremendous symbolic power. And he's not alone.
Here's a map, originally published last year around the time of a number of other royal abdications, showing the remaining few dozen monarchies on the planet. You can read more about each surviving monarchy here.
Some corrective notes: 1) The colors of Cambodia and Thailand should be flipped. 2) Most monarchs are technically heads of state. The countries in red indicate where monarchs maintain political authority. 3) Although some countries in the Commonwealth of Nations still have the British queen as the head of state, the majority, particularly former colonies in Africa and Asia, became independent republics and rejected the British monarchy.