Which countries are separated by a geometric border?

The choice of North Korea and South Korea as countries separated by a geometric border is based on the nature of the Korean Demilitarized Zone (DMZ). This DMZ was established at the end of the Korean War in 1953 and features straight lines and fixed geographical coordinates that define the boundary between the two nations. This geometric character stands out in contrast to more natural borders, which may follow rivers, mountain ranges, or other landmarks.

The DMZ is not only a physical barrier but also a symbol of the ongoing political tension and division on the Korean Peninsula. It highlights the impact of historical conflict leading to a division that is marked by an artificial, man-made line, rather than by natural topographical features.

Other options involve borders that are influenced by geographical features or historical agreements, which does not classify them as purely geometric. For example, the borders between Turkish Cyprus and Greek Cyprus are partially based on the ethnic composition of the island and historical claims rather than a strictly geometric demarcation. The border between France and Spain runs along the Pyrenees mountains, which are natural geographic features. Similarly, the border between England and Ireland takes into account historical disputes and natural features, rather than being defined by straight lines or specific geometric coordinates.