Border
Borders are generally defined as geographical boundaries, imposed either by features such as oceans and terrain, or by political entities such as governments, sovereign states, federated states, and other subnational entities. Political borders can be established through warfare, colonization, or mutual agreements between the political entities that reside in those areas.
Some borders—such as most states' internal administrative borders, or inter-state borders within the Schengen Area—are open and completely unguarded. Most external political borders are partially or fully controlled, and may be crossed legally only at designated border checkpoints; adjacent border zones may also be controlled. For the purposes of border control, airports and seaports are also classed as borders. Most countries have some form of border control to regulate or limit the movement of people, animals, and goods into and out of the country. Under international law, each country is generally permitted to legislate the conditions that have to be met in order to cross its borders, and to prevent people from crossing its borders in violation of those laws.
File:Panmunjeom DMZ.png|thumb|South Korean policemen standing guard at the North Korea-South Korea border. View from South Korea.
Buffer zones may be set up on borders between belligerent entities to lower the risk of escalation. While border refers to the boundary itself, the area around the border is called the frontier.
History
In the pre-modern world, the term border was vague and could refer to either side of the boundary, thus it was necessary to specify part of it with borderline or borderland. During the medieval period the government's control frequently diminished the further people got from the capital. Therefore borderland attracted many outlaws, as they often found sympathizers.File:CIA, Conrad Schumanns Sprung in die Freiheit, August 1961 1.jpg|thumb|Konrad Schumann, an East German border guard, fleeing East Germany towards West Germany in 1962
In the past, many borders were not clearly defined lines; instead there were often intervening areas often claimed and fought over by both sides, sometimes called marchlands. Special cases in modern times were the Saudi Arabian–Iraqi neutral zone from 1922 to 1991 and the Saudi Arabian–Kuwaiti neutral zone from 1922 until 1970. In modern times, marchlands have been replaced by clearly defined and demarcated borders.
Classification
Political borders
Political borders are imposed on the world through human agency. That means that although a political border may follow a river or mountain range, such a feature does not automatically define the political border, even though it may be a major physical barrier to crossing.Political borders are often classified by whether or not they follow conspicuous physical features on the earth. William Miles said that Britain and France traced close to 40% of the entire length of the world's international boundaries.
Natural borders
Natural borders are geographical features that present natural obstacles to communication and transport. Existing political borders are often a formalization of such historical, natural obstacles.Some geographical features that often constitute natural borders are:
- Oceans: oceans create very costly natural borders. Very few countries span more than one continent. Only very large and resource-rich states are able to sustain the costs of governance across oceans for longer periods of time.
- Rivers: Some political borders have been formalized along natural borders formed by rivers. If a precise line is desired, it is often drawn along the thalweg, the deepest line along the river.
- Lakes: larger lakes create natural borders.
- Forests: denser jungles or forests can create strong natural borders.
- Mountain ranges: Many nations have their political borders defined along mountain ranges, often along a drainage divide.
Landscape borders
A landscape border is a mixture of political and natural borders. One example is the defensive forest created by China's Song dynasty in the eleventh century. Such a border is political in the sense that it is human-demarcated, usually through a treaty. However, a landscape border is not demarcated by fences and walls but instead landscape features such as forests, mountains, and water bodies. It is different from a natural border, however, in the sense that the border landscape is not natural but human-engineered. Such a landscape usually differs from the borderland's natural geography and its building requires tremendous human labour and financial investment.Geometric borders
Geometric boundaries are formed by straight lines, or occasionally arcs, regardless of the physical and cultural features of the area. Such political boundaries are often found around the states that developed out of colonial holdings, such as in North America, Africa and the Middle East. The Canada–United States border follows the 49th parallel for roughly from Lake of the Woods west to the Pacific Ocean.Fiat borders
A generalization of the idea of geometric borders is the idea of fiat boundaries by which is meant any sort of boundary that does not track an underlying bona fide physical discontinuity. Fiat boundaries are typically the product of human demarcation, such as in demarcating electoral districts or postal districts.Relic borders
A relic border is a former boundary, which may no longer be a legal boundary at all. However, the former presence of the boundary can still be seen in the landscape. For instance, the boundary between East and West Germany is no longer an international boundary, but it can still be seen because of historical markers on the landscape; it remains a cultural and economic demarcation in Germany. Other examples include the Demilitarized Zone between North and South Vietnam and the border between North and South Yemen. Occasionally a relic border is reconstituted in some form, for example the border between British Somaliland and Italian Somaliland ceased to exist when the two colonies merged to form the independent state of Somalia in 1960, however when the former British Somaliland declared independence in 1991 it claimed the former British-Italian line as its eastern border.Lines of control
A line of control refers to a militarized buffer border between two or more nations that has yet to achieve permanent border status. LoC borders are typically under military control and are not recognized as an official international border. Formally known as a cease-fire line, an LoC was first created with the Simla Agreement between India and Pakistan. Similar to a cease-fire line, an LoC is typically the result of war, military stalemates and unresolved land ownership conflict.Maritime borders
A maritime border is a division enclosing an area in the ocean where a nation has exclusive rights over the mineral and biological resources, encompassing maritime features, limits and zones. Maritime borders represent the jurisdictional borders of a maritime nation and are recognized by the United Nations Convention on the Law of the Sea.Maritime borders exist in the context of territorial waters, contiguous zones, and exclusive economic zones; however, the terminology does not encompass lake or river boundaries, which are considered within the context of land boundaries.
Some maritime borders have remained indeterminate despite efforts to clarify them. This is explained by an array of factors, some of which illustrate regional problems.
Airspace borders
is the atmosphere located within a country's controlled international and maritime borders. All sovereign countries hold the right to regulate and protect air space under the international law of Air sovereignty. The horizontal boundaries of airspace are similar to the policies of "high seas" in maritime law. Airspace extends 12 nautical miles from the coast of a country and it holds responsibility for protecting its own airspace unless under NATO peacetime protection. With international agreement a country can assume the responsibility of protecting or controlling the atmosphere over International Airspaces such as the Pacific Ocean. The vertical boundaries of airspace are not officially set or regulated internationally. However, there is a general agreement of vertical airspace ending at the point of the Kármán line. The Kármán line is a peak point at the altitude of 62 mi above the Earth's surface, setting a boundary between the atmosphere and outer space.Frontier
The frontier is a border that is open-ended to one side, identifying an expanding borderland to one side.This type of border can be fairly abstract and has been identified as a particular state of mind for human activity. As such frontiers have been applied to borderlands identifying and claiming them as terra nullius, such as Marie Byrd Land in West Antarctica, the only territory in Antarctica unclaimed by any sovereign nation.