Berlin border crossings
The Berlin border crossings were border crossings created as a result of the post-World War II division of Germany. Prior to the construction of the Berlin Wall in 1961, travel between the Eastern and Western sectors of Berlin was completely uncontrolled, although restrictions were increasingly introduced by the Soviet and East German authorities at major crossings between the sectors. This free access, especially after the closure of the Inner German border, allowed the Eastern Bloc emigration and defection to occur. East German officials, humiliated by this mass defection, subsequently chose to erect the Berlin Wall in  order to prevent residents from leaving East Germany. After the construction of the Berlin Wall in 1961, border stations between East Berlin (regarded as East Germany's capital by the German Democratic Republic but unrecognized by the Western Allies) and the sectors controlled by those three Western Allies were created. Although there were few crossings at first, more sites were built over the wall's lifespan. Many East Germans crossed the wall illegally by climbing over it, sailing around it, or digging under it, while many others died while attempting to cross. Border control procedures. Between West Berlin and German  Democratic Republic (GDR) territory, the border stations were developed very effectively on the GDR side. (The official designation for controlled border traffic was "Grenzübergangsstelle, GÜSt": border crossing site.) Border officials and customs agents would monitor incoming and outgoing traffic according to established procedures, at times with the utmost scrutiny. A strict division of labor among the various organizations was the rule. The security of the outward-facing border and of the border crossings was maintained by special security divisions of the GDR border guard troops (German abbreviation "SiK", short for "Sicherungskompanien"). The actual inspections of vehicle and pedestrian traffic were  carried out by the passport control units (German abbreviation "PKE", short for "Passkontrolleinheiten"). The PKE units were not under the command of the GDR border guard troops and thereby the Ministry of Defense, but the Ministry for State Security (Division VI / Department 6, Passport Control). While on duty at the border stations, however, the PKE would wear the same uniforms as the border guard troops. For personal inspections, highly qualified and specially trained forces were used exclusively. The passports, identification cards, etc., could be transmitted from the inspection sites to a processing center using closed-circuit television and ultraviolet light , where they were recorded. From there, commands were issued using a numeric display to the passport control unit, for example "flip page", "request additional documentation", "delay processing", ask predefined questions, etc. On the West Berlin side, police and customs agents were stationed. No personal inspections usually took place there. Who could cross. West Germans and citizens of other Western countries could in general visit East Germany. Usually this involved application of a visa at an East German embassy several weeks in advance. Visas for day trips restricted to East Berlin were issued without previous application in a simplified procedure at  the border crossing. However, East German authorities could refuse entry permits without stating a reason. In the 1980s, visitors from the western part of the city who wanted to visit the eastern part had to exchange at least DM 25 into East German currency at the poor exchange rate of 1:1. It was forbidden to export East German currency out of the East, but money not spent could be left at the border for possible future visits. Tourists crossing from the west had to also pay for a visa, which cost DM 5; West Berliners did not have to pay  this. West Berliners initially could not visit East Berlin or East Germany at all. All crossing points were closed to them between 26 August 1961 and 17 December 1963. In 1963, negotiations between East and West resulted in a limited possibility for visits during the Christmas season that year (""). Similar very limited arrangements were made in 1964, 1965 and 1966. In 1971, with the Four Power Agreement on Berlin, agreements were reached that allowed West Berliners to apply for visas to enter East Berlin and East Germany regularly, comparable to the regulations already in force for West Germans. However, East  German authorities could still refuse entry permits. East Berliners and East Germans could at first not travel to West Berlin or West Germany at all. This regulation remained in force essentially until the fall of the wall, but over the years several exceptions to these rules were introduced, the most significant being: However, each visit had to be applied for individually and approval was never guaranteed. In addition, even if travel was approved, GDR travelers could exchange only a very small amount of East German Marks into Deutsche Marks (DM), thus limiting the financial resources available for them to travel  to the West. This led to the West German practice of granting a small amount of DM annually ("Begrüßungsgeld", or welcome money) to GDR citizens visiting West Germany and West Berlin, to help alleviate this situation. Citizens of other East European countries except Yugoslavia were in general subject to the same prohibition on visiting Western countries as East Germans, though the applicable exception (if any) varied from country to country. Citizens of Hungary could freely cross into West Berlin from 1 January 1988. Border crossings up to 1990. On 13 August 1961, the crossings were at Kopenhagener Straße, Wollankstraße, Bornholmer  Straße, Brunnenstraße, Chausseestraße, Brandenburger Tor, Friedrichstraße, Heinrich-Heine-Straße, Oberbaumbrücke, Puschkinallee, Elsenstraße, Sonnenallee, Rudower Straße. The Kopenhagener Straße, Wollankstraße, Brunnenstraße, Puschkinallee, Elsenstraße and Rudower Straße were closed on 23 August 1961, and in return, Invalidenstraße checkpoint was opened. West Berlin – East Berlin. There were several border crossings between East and West Berlin: In addition, entirely located in East Berlin (reached by streetcar, underground, or railroad): West Berlin – GDR. Crossings for transit traffic. Road crossings. These crossings could be used for passage on the prescribed transit highways and for travel within the SOZ/GDR: Waterways. The numerous border crossings on waterways  (e.g., Spree, Havel, Teltow Canal) were only open to commercial freight traffic. Recreational boats had to be loaded onto ships or towed overland. Air travel. To and from Berlin-Schönefeld Airport for air travel: also, within East Berlin territory (access via streetcar, U-bahn or rail): At the Berlin-Tempelhof and Berlin-Tegel airports there were border crossings manned by West Berlin police and customs. These were not located in territory controlled by the GDR. In addition to processing for international air travel, the personal documents of travelers between West Berlin and the Federal Republic were inspected. Miscellaneous crossings. The  various illegal or unofficial border crossings are not reliably documented: Changes in 1989 and 1990. In the time between the fall of the Berlin Wall on 9 November 1989 and the abolition of all border controls on 1 July 1990, numerous additional border crossings were built for interim use. Because of their symbolic value, the most famous of these were Glienicke Bridge, Bernauer Straße, Potsdamer Platz, and the Brandenburg Gate. The opening of the Brandenburg Gate was merely a public relations formality which took place on 22 December 1989 at the request of then-Chancellor Helmut Kohl. Hundreds of television  crews from all over the world had anticipated this historic event for weeks. West Germans and West Berliners were allowed visa-free travel to the East Berlin and East Germany starting 23 December 1989. Until then, they could only visit under restrictive conditions that involved application for a visa several days or weeks in advance and obligatory exchange of at least 25 DM per day of their planned stay. Thus, in the weeks between 9 November 1989 and 23 December 1989, East Germans could travel more freely than Westerners as they were able to cross into West Berlin with just  passport checks. There are also roads that are reopened between 12 June 1990 and 21 June 1990 with or without border controls. The controls were abandoned on 1 July 1990, the day of the currency union and before the actual reunification of Germany on 3 October 1990. In the months after the fall of the Wall, border crossings between the East and the West had become more and more irrelevant. Today, a few portions of the structures have been retained as a memorial. Remaining border controls. Today the only remaining border crossings in Berlin are located at Tegel and Schönefeld  airports (Schönefeld being located outside Berlin city limits) and all Cold War-specific border control procedures have disappeared altogether. They are staffed by German Federal Police and Customs for normal international traffic screening purposes.