Metro Line M4 (Budapest Metro) Metro Line M4 (Budapest Metro) Line 4 (officially: South Buda–Rákospalota (DBR) Line, Metro 4 or M4, and unofficially: Green Line), is the fourth line of the Budapest Metro. It opened on 28 March 2014. The first section, 7.4 km in length and consisting of ten stations, connects the southwestern Kelenföld vasútállomás located in Buda, and the eastern Keleti pályaudvar in Pest, under the River Danube. While three additional sections — one an eastern extension to Bosnyák tér, the second west to Virágpiac, and a third further east to Újpalota — have been planned, these remain unfunded by the Budapest city
Budapest are currently 837 different monuments, which represent the most of the European artistic style. The classical and unique Hungarian Art Nouveau buildings are prominent. A lot of libraries have unique collections in Budapest, such as the National Széchenyi Library, which keeps historical relics from the age before the printing of books. The Metropolitan Szabó Ervin Library plays an important role in the general education of the capital's population. Other libraries: The Library of the Hungarian Academy of Sciences, Eötvös University Library, the Parliamentary Library, Library of the Hungarian Central Statistical Office and the National Library of Foreign Literature. In Budapest