Children who will become kings and queens in the future. Elizabeth, Crown Princess of Belgium (age 22). Catharina-Amalia, Princess of the Netherlands (age 19). Ingrid Alexandra, princess of Norway (age 19). Christian, Prince of Denmark (age 18). Leonor, Princess of Spain (age 18). Estelle, Princess of Sweden (age 11). George, Prince of the United Kingdom (age 10). Jacques, Crown Prince of Monaco (age 8).