The Kingdom of the Netherlands commonly known simply as the Netherlands, consists of 4 constituent (Autonomous administrative division) countries Aruba, Curaçao, the Netherlands, and Sint Maarten. These territories united under the monarch of the Netherlands His Majesty Willem-Alexander, who functions as head of state. 

In practice, however, most of the Kingdom's affairs are administered by the Netherlands—which comprises roughly 98% of the Kingdom's land area and population—on behalf of the entire Kingdom. Consequently, Aruba, Curaçao, and Sint Maarten are dependent on the Netherlands for matters like foreign policy and defense, but are autonomous to a certain degree, with their own parliaments. 

The vast majority of land area of the constituent country of the Netherlands is in Europe, while its three special municipalities (Bonaire, Saba, and Sint Eustatius) are located in the Caribbean, as are the other three constituent countries. The Kingdom has a population in the Netherlands of 17,821,419 (as of January 2023), and of 29,418 (as of November 2023) in Bonaire, Saba, and Sint Eustatius.

Country capital is Amsterdam, which is colloquially referred to as the "Venice of the North", for its large number of canals, now a UNESCO World Heritage Site.   

Source: Wikipedia