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 (such as lines of latitude or longitude), or occasionally arcs (Pennsylvania/Delaware), 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 (Ontario and Minnesota) 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, latin for “let it be done”, a decision). 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 (defunct since 1975) and the border between North and South Yemen (defunct since 1990). 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 (LoC) refers to a militarized buffer border between two