Medan is the third biggest city in Indonesia after Jakarta and Surabaya. Medan Sumatra is, after Greenland, New-Guinee and Borneo, the biggest island in the world with a surface of 473,481 sq.km. - ten times as big as Holland. The island knows big regional differences and it's cut in eight pieces for governmental reasons. Until a certain level, this partition is fixed more over ethnical barriers than by geographical borders.