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 became the co-capital of the Austro-Hungarian Empire, a great power that dissolved in 1918, following World War I. The city was the focal point of the Hungarian Revolution of 1848, the Battle of Budapest in 1945, and the Hungarian Revolution of 1956. Budapest is an Alpha- global city with strengths in commerce, finance, media, art, fashion, research, technology, education, and entertainment. It is Hungary's financial centre and the highest ranked Central and Eastern European city on Innovation Cities Top 100 index, as well ranked as the second fastest-developing urban economy in Europe. Budapest is host to many major international organization's