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 terms of the hardiness zone. As per the 1981-2010 climatological norm, widely used in most other European countries, the climate in Budapest has shifted to humid subtropical (Köppen "Cfa"), with averages above 0 °C in the coldest month and above 22 °C in the warmest. Budapest has architecturally noteworthy buildings in a wide range of styles and from distinct time periods, from the ancient times as Roman City of Aquincum in Óbuda (District III), which dates to around 89 AD, to the most modern Palace of Arts, the contemporary arts museum and concert hall. Most buildings in Budapest are relatively