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 there are forty theatres, seven concert halls and an opera house. Outdoor festivals, concerts and lectures enrich the cultural offer of summer, which are often held in historical buildings. The largest theatre facilities are the Budapest Operetta and Musical Theatre, the József Attila Theatre, the Katona József Theatre, the Madách Theatre, the Hungarian State Opera House, the National Theatre, the Vigadó Concert Hall, Radnóti Miklós Theatre, the Comedy Theatre and the Palace of Arts, known as "MUPA". The Budapest Opera Ball is an annual Hungarian society event taking place in the building of the Budapest Opera ("Operaház") on the last