In military language, a demilitarized zone or DMZ is an area, usually the frontier between certain military forces, where military activity is not permitted at all. The fact that a certain zone is a demilitarized zone is usually agreed upon by bilateral or multilateral agreements, in the context of an armistice or of a treaty. In most cases, the DMZ stretches along a line of control and actually represents a de-facto border between two regions or countries.
In general, demilitarized zones are neutral territories. This means that none of the two belligerents is allowed to control it or to conduct any sort of military activity on it. However, in certain cases, certain demilitarized zones remained demilitarized even after a treaty was signed, awarding control to one of the parties involved over that specific area.
Sometimes conflicting powers decide upon the demilitarization of a zone without formally resolving their conflict about territorial claims. This means that in such cases military actions are replaced by diplomatic dialogues, international mediation or other types of negotiations. Sometimes the conflict is just frozen and restarts some time later.
In many cases, people who say DMZ think Korea. The Korean Demilitarized Zone is a strip of land in the peninsula and it separates North Korea from South Korea. It is about 160 miles long and around two miles and a half wide.
After the 3 years war between North Korea and South Korea, the armistice that was signed in 1953 specified that each of the two sides would move their troops back by 2000 meters. A buffering zone was created. Only two villages were allowed to remain within the perimeter of the DMZ. The villagers are under United Nations protection and are required to spend the most part of the year in the village in order to be able to keep their residency.