revolt that lasted from 23 October until 11 November. After Nagy had declared that Hungary was to leave the Warsaw Pact and become neutral, Soviet tanks and troops entered the country to crush the revolt. Fighting continued until mid November, leaving more than 3000 dead. A monument was erected at the fiftieth anniversary of the revolt in 2006, at the edge of the City Park. Its shape is a wedge with a 56 angle degree made in rusted iron that gradually becomes shiny, ending in an intersection to symbolize Hungarian forces that temporarily eradicated the Communist leadership. From the 1960s to the late 1980s Hungary was often satirically referred to as "the happiest barrack" within the Eastern bloc, and much of the wartime damage to the city was finally repaired. Work on Erzsébet Bridge, the last to be rebuilt, was finished in 1964. In the early 1970s, Budapest Metro's east–west M2 line was first opened, followed by the M3 line in 1976. In 1987, Buda Castle and the banks of the Danube were included in the UNESCO list of World Heritage Sites. Andrássy Avenue (including the Millennium Underground Railway, Hősök tere, and Városliget) was added to the UNESCO list in 2002. In the 1980s, the city's population reached 2.1 million. In recent times a significant decrease in population occurred mainly due to a massive movement to the neighbouring agglomeration in Pest county, i.e., suburbanisation. In the last decades of the 20th century the political changes of 1989–90 (Fall of the Iron Curtain) concealed changes in civil society and along the streets of Budapest. The monuments of the dictatorship were removed from public places, into Memento Park. In the first 20 years of the new democracy, the development of the city was managed by its mayor, Gábor Demszky. Geography Topography Budapest, strategically placed at the centre of the Carpathian Basin, lies on an ancient route linking the hills of Transdanubia with the Great Plain. By road it is south-east of Vienna, south of Warsaw, south-west of Moscow, north of Athens, north-east of Milan, and south-east of Prague. The area of Budapest lies in Central Hungary, surrounded by settlements of the agglomeration in Pest county. The capital extends in the north–south, east–west direction respectively. The Danube enters the city from the north; later it encircles two islands, Óbuda Island and Margaret Island. The third island Csepel Island is the largest of the