The communist German Democratic Republic was established in the historic "Mitteldeutschland" ( Middle Germany ). Former German territories east of the Oder and Neisse rivers, mainly the Prussian provinces of Pomerania , East Prussia , West Prussia , Upper Silesia , Lower Silesia , the eastern Neumark of Brandenburg , and a small piece of Saxony were thus detached from Germany. To compensate Poland for the USSR's annexation of its eastern provinces, the Allies provisionally established Poland's post-war western border at the Oder–Neisse line at the Yalta Conference (1945). As a result, most of Germany's central territories became the Sowjetische Besatzungszone (SBZ, Soviet Occupation Zone). All other lands east of the Oder–Neisse line were put under Polish administration, with the exception of historic northern East Prussia , which went to the USSR. 
East German officials today opened the Berlin Wall, allowing travel from East to West Berlin. The following day, celebrating Germans began to tear the wall down. One of the ugliest and most infamous symbols of the Cold War was soon reduced to rubble that was quickly snatched up by souvenir hunters. The East German action followed a decision by Hungarian officials a few weeks earlier to open the border between Hungary and Austria. This effectively ended the purpose of the Berlin Wall, since East German citizens could now circumvent it by going through Hungary, into Austria, and thence into West Germany. The decision to open the wall was also a reflection of the immense political changes taking place in East Germany, where the old communist leadership was rapidly losing power and the populace was demanding free elections and movement toward a free market action also had an impact on President George Bush and his advisors. After watching television coverage of the delirious German crowds demolishing the wall, many in the Bush administration became more convinced than ever that Soviet leader Mikhail Gorbachev’s statements about desiring a new relationship with the West must be taken more seriously. Unlike 1956 and 1968, when Soviet forces ruthlessly crushed protests in Hungary and Czechoslovakia, respectively, Gorbachev actually encouraged the East German action. As such, the destruction of the Berlin Wall was one of the most significant actions leading to the end of the Cold War.